How it happens
There are a few ways multiples can occur. The most common way is naturally, from sexual intercourse. In recent decades reproductive drugs to stimulate ovulation or to artificially implant one or more fertilised eggs have produced twins and super twins (more than two babies).
Either a mother releases two (or more) ovum/eggs during ovulation which when fertilised produce Dizygotic (DZ) twins or fraternal/ non-identical babies or, one fertilised embryo can split into two and produce two embryos known as Monozygotic (MZ) twins or identical/paternal twins. DZ twins can either be two boys, two girls or one of each. MZ twins are always the same sex (not everyone actually knows this and even when they know they are identical will still ask if they’re a boy and girl!!) According to Pathologist Geoffrey Machin MZ twins are not necessarily genetically identical. There is a third type of twin called Sesquizygotic (sesqui is Latin for one and a half) twins where one ovum splits in two and then they are each fertilised by separate sperm. It’s not clear to me why the ovum splits like this without the sperm to stimulate it but it’s certainly a fascinating combination that is rarely spoken about.
It is possible for DZ twins to be conceived at different times. If the hormones aren’t high enough yet a woman may ovulate a second time, even a month after the first ovum is fertilised. It isn’t uncommon for single women to get pregnant with twins as the body is not used to the stimulation of hormones in semen and will ovulate again taking the ‘rare opportunity’ when it arrives to procreate.
Once the embryo(s) reach the uterus for implantation certain things can happen. The two embryos of DZ twins will implant into the uterine wall and each will produce their own placenta and their own amnions (the amniotic water chamber a baby develops in) and chorions (the outermost membrane around the developing baby). Sometimes the placenta of DZ twins can fuse to look like one. If they are the same sex it may be wrongly thought that they are identical.
With MZ twins it depends when the embryo splits as to whether you get one or two implantations. If the embryo splits early enough they will implant separately, have their own placentas and their own amnions and chorions. They may appear to be DZ twins, but a blood test once they are born will confirm. Sometimes the placenta will fuse together. Most commonly MZ twins will have one placenta, one chorion and two amnions. If the embryo splits after implantation then the two babies will share one placenta, one chorion and one amnion but this is rare.
The sharing of placentas, amnions and chorions is significant for the predicted health of the babies. A placenta each is thought to be healthier than a placenta shared as they are not sharing the blood flow. Separate amnions and chorions are safer as there is less likelihood of the babies getting tangled in each other’s umbilical cords. Also if, tragically, one baby were to die, having separate amnions will prevent the live baby from being affected.
When there are more than two babies any combination of the above can happen. Two of the babies may be MZ and the other not or all three could be from single embryos. Most commonly quadruplets are formed from separate eggs, but potentially they could be made from two MZ embryos. Quads could even come from one single embryo that splits in two and then each of those split in two again!
Midwife or Obstetrician?
A midwife who is experienced with twin births may be the ideal care for a healthy pregnancy. In New Zealand we have many independent midwives who are very experienced with births in general but may not want to support a twin birth. This can sometimes be more to do with politics (their statistics) than the ability of a woman to birth twins. Also legal issues, fears of something going wrong and being sued, are a big deciding factor for many midwives/obstetricians. Sometimes it can be personal in that she’s had a bad experience with a twin birth and no longer feels suitable to provide support. Strangely enough these same health professionals can have problem births with singletons in a hospital but not change their practise in the same way. Being unable to find a supportive midwife or the idea that birthing multiples is more dangerous than singletons leads many people to choose an obstetrician as their lead maternity carer (LMC). During the birth there will always be a midwife present. If you know and trust the midwife already then you’re off to a good start. Some people opt for ‘shared care’ where the midwife is the LMC and pay a small fee for an obstetrician of their choice to attend the birth.
The key to finding someone to support you with a natural twin birth and especially a vaginal breech birth is to keep looking. Don’t take one response as the response of everyone. The benefits to mother and baby from birthing as nature intended are well documented and understood. It would be a very sad thing to steal this from a mother and her babies purely because of a ‘just in case’ attitude.
Changes in level of care
Whether you have a midwife or an obstetrician, you will be expected to have more regular visits, either to your midwife or also to a specialist hospital department, and more ultrasound scans. In New Zealand you will generally have a scan every two weeks of your pregnancy. All care is optional so if you don’t feel comfortable with lots of scans during pregnancy then you can ask not to have them. Pressure may be put on you but with the latest research showing that the increase in scans is correlated with slightly lower birth weight (something of great concern with multiples) (and also an increase in left handedness) I think you’ll be in your right to stand your ground. It is important to carry on with the normal urine tests and make sure each baby is growing well.
“Our 2008 Tamba survey revealed that almost 9 out of 10 women (87%) received no specific nutritional advice for a multiple pregnancy, apart from vague instructions to ‘eat healthily’. Although in the USA health professionals sometimes recommend following a high calorie diet, internationally there has not been a great deal of research conducted on nutrition in multiple pregnancies and therefore we have not included this advice.” Of all people – it’s even more important for women carrying multiples to receive good nutritional advice.
To produce a healthy baby a woman’s normal nutritional requirement will increase. She’ll get hungrier and want to eat more often. When carrying twins and super twins the need for extra nutrition increases the same again with each baby carried. This means that a woman will need to eat even more regularly than if she were carrying just one baby. In the last trimester, grazing is best.
It is dangerous to tell a woman with multiples to watch her weight. She needs to eat enough healthy food to keep her energised and functioning optimally as well as growing two or more little people. Eating two or more pieces of cake or having a second or third portion of chips is not going to produce healthy people even though it increases her caloric intake. Eating extra portions of good quality fruit, vegetables, nuts, eggs, fish, whole grains, meat, pulses etc. will create healthy people. Lots more protein and happy fats are required as these are the building blocks of each and every cell and fuel for healthy functioning.
If a woman does not eat enough protein mixed with other healthy calories she will run the risk of using the protein as fuel rather than building blocks to healthy development. For example, a high protein diet and low carbs will result in the protein being used ineffectively. A pregnant woman with multiples has even higher blood volume than singletons. This requires higher levels of protein to facilitate the process. If her protein is being used as fuel then her blood volume will not expand appropriately which may affect how much nutrition is delivered to her babies. Many people don’t know this.
I have already written a lot on pregnancy nutrition so will not cover it all again here. But it is safe to say that a woman with multiples must eat much more than those with singletons if she expects to grow healthy babies to term. If her body cannot cope with the nutritional demands of her babies then the babies may be born pre-term in order to survive or make it to term but be unhealthily underweight.
“Your goal, especially in pregnancy, is to eat more complex carbohydrates in their less processed, more natural form. One-third to one half of your diet should be whole grains… Excess calories actually improve protein digestibility and an extra 700 to 1000 calories can spare protein by 30 and 50 per cent respectively… Omega-3 fatty acids are important for brain chemicals, serotonin and dopamine, that affect moods. Many women start their pregnancies already deficient in omega-3 fatty acids and each baby will deplete her stores… EFAs [essential fatty acids] are needed by every cell of your body and your babies’ bodies, especially the cell walls and for the absorption of trace minerals that activate a large number of enzymes… Selenium and iodine, like EFAs, are needed for brain development. Magnesium, calcium, and zinc are involved in the body’s use of omega-3(catalysts) and have been explored as preventative agents for preterm labour”
Growing babies isn’t about a bit of extra nutrition to keep you going. It’s about actually making a whole new person purely out of the food and water you eat/drink and the oxygen you breathe. If you don’t put enough in you can’t expect to grow and develop healthy babies to full term.
For more detailed information about nutrition with multiples I definitely recommend reading Elizabeth Noble’s book Having Twins & More.
Possible problems associated with multiples
The biggest problem facing a multiple pregnancy is low birth weight and pre-term labour. As spoken about above nutrition plays a very big role in the healthy size of unborn babies and deficiencies can contribute to early labour. Each baby is an individual developing in the same way as all babies do (whether they’re twins or singletons). If a singleton baby is born at 34 weeks they may have the same troubles as twin babies born at 34 weeks. However, if the twin babies’ mother hasn’t been eating enough (usually because she hasn’t been told just how much more to eat) then they could be dangerously underweight and this can create even more issues for their survival. Even though nobody knows this for sure, I believe that when multiples or even singletons aren’t getting enough nutrition, they will facilitate being born as a means of survival.
Another cause for low birth weight and pre-term labour is Twin to Twin Transfusion Syndrome (TTTS). This rare condition (6% of multiple pregnancies) may happen when a placenta is shared, or more normally if the same circulation is shared. This is why it’s important to know if there is one or more placenta, amnion and chorion. If both babies are sharing everything then a close eye is needed to make sure they are growing at a healthy rate. Sometimes one baby can receive more nutrients and fluid creating problems for themselves as well as the other. The smaller twin may become anaemic and the bigger twin may receive too much blood putting a strain on their heart. I have seen many sets of twins where you can see the one who received better nutrition and the other compromised nutrition.
Risk factors for pre-term labour (babies born too early and need help to survive)
- Poor nutrition or inadequate hydration
- Insufficient Omega-3’s in the diet
- Physical trauma
- Hard physical labour, tiring travel, standing all day at work
- Substance abuse
- Emotional stress and fear
- Financial stress
- Fear of increased body size by term
- Fear of birthing two or more babies
- Low pre-pregnancy weight
- Chronic coughing
- Placental problems
- Toxaemia (pre-eclampsia, eclampsia etc.)
- Infection in the genital tract
- Congenital abnormalities and congenital heart disease/defect
- Fibroids (benign uterine tumours)
- Diabetes mellitus (true diabetes not gestational diabetes)
- Insufficient or excessive amniotic fluid (oligohydramnios or polyhyrdamnios)
- Exposure to x-rays, anaesthetic gases and lead
- Car accident or injury
- Severe gum disease
- Two or more second trimester abortions
Length of gestation
A normal healthy singleton baby in a good position will normally be born around 40 week’s gestation. Having two or more babies will often bring the birth day earlier. It could be enough nutrition and oxygen for both babies is becoming harder so labour is naturally instigated. Since a woman can carry quads and octuplets I do not believe the weight or space are the factors that determine when a multiple pregnancy starts labour.
These days, because women are often not eating enough for multiples, labour may start before 38 weeks. According to an Australian study of 235 women those that carry on past 38 weeks have been found to be at higher risk of complications but it is not clear from this study what the mother was eating day to day.
I believe that if it’s not ideal for a singleton to be born before 38 weeks why would it be ideal for a twin or triplet to be born so early? If we can discover why there are complications past 38 weeks we can address them rather than making sweeping statements that everyone should be induced and put them at risk of inductions and caesareans. Again, I believe it is related to the quality and amount of nutrition. I worked with a woman carrying triplets and they were birthed at 36 weeks with two weighing over five pounds and one weighing 4.8 pounds. We do know that the longer multiples can be carried in the womb, the healthier they will be.
“Multiple pregnancies are generally less likely to carry to full term (40 weeks for singleton births, 37 weeks for twin births, and 34 weeks for triplet births). In the 2008 Tamba survey, only 43% of twin pregnancies and 1.5% of triplet pregnancies lasted over 37 weeks.”
I’m actually quite excited by the statistic that 43% of twins go past 37 weeks. I was born with my twin at 36 weeks and spent time in NICU before being allowed home. I’m more interested in research that looks at good nutrition of multiple pregnancies and allows births to happen spontaneously. Hopefully one day I will come across that study. At the present time most twin pregnancies are induced at 38 weeks ‘just in case’.
With some pregnancies a baby isn’t healthy enough or the circumstances aren’t right and the baby dies or the pregnancy is terminated (the baby’s life is medically stopped). This is often traumatic for the mother and can be felt for a life time.
Twin pregnancies can create a different set of moral heartbreaks. For instance, if carrying two or more babies is putting each baby at risk but allowing one to die will save the life of the other then the decision needs to be made as to who will be killed. It may be clear that one baby won’t survive and needs to be killed to save the life of the other but this is still very hard to come to terms with for many people. It’s important that both parents get the correct nurturing and support when going through such an experience.
Choosing to end the life of one of the babies carries a high risk of pre-term labour (75%) and also runs the risk of infection (through the injection of the poison) and also the possibility of either choosing the wrong baby or even failing to kill the baby properly.
Occasionally one twin or a super twin will die naturally. Whether the baby has had to be killed or he/she dies naturally it’s not possible to remove the dead baby early as this will put the living baby at risk. The mother is then required to carry all babies to term and give birth to one or more live and one or more dead babies. It’s often very difficult for the mother to celebrate the life of the living baby when overshadowed by the grief of losing the dead baby. This is why it is so important to address grieving in childbirth classes and to actually give women an opportunity to grieve a loss where they feels supported.
Likewise if they to full term with two or more babies and one dies during the birth it’s incredibly difficult to handle the emotions of elation with one (or more) baby and the grief of the other. Many people will brush your emotions off with “at least you still have one (or more)”. Imagine if they said that if you had two grown children and one died! It really is the same situation.
“Rates of still births are low but there continues to be an increased risk for multiple births from 0.57% for singletons to 1.3% for twins, 5.1% for triplets and 10% for quads (source: ONS, 2004). Several studies have also shown the incidence of cerebral palsy to be higher in multiple births, which is mainly attributable to the higher levels of prematurity and lower birth weights in multiple births.”
Although still birth is incredibly low a medical professional can still scare you by saying twins are twice as likely to be still born as singletons. What they may not tell you is that 99.43% of singletons and 98.7% of twins are born alive. It is important to focus on the positive, especially when the rate of normal birth is so high.
Determining whether or not to birth your babies vaginally or by caesarean can often depend on the positioning of each baby. It’s rare these days for super twins to be born vaginally although I have heard of natural triplet deliveries.
Women are often told different things by different doctors or midwives. Often if the first baby is head down a vaginal delivery is supported, although some midwives and obstetricians don’t feel safe supporting a vaginal twin delivery at all. Some obstetricians won’t deliver a breech second baby even though the risks of incomplete dilation are not an issue, but some will. If the first baby is breech and you want a vaginal birth then you will need to find a fantastic midwife and obstetrician who believe in you and will stand up to the pressure put upon them by other hospital staff. I honor those that do!
I nearly supported a double breech twin birth as a doula but unfortunately at 39 weeks during an ultrasound scan we discovered the first baby had the umbilical cord between her feet. This meant that it was unsafe to birth vaginally and a caesarean was given.
During the birth
The trouble with birth today is that it’s so routinely interrupted that we actually have very little evidence and research that shows what happens in truly natural birth situations. This is never more apparent than with the birth of multiples. Each baby comes out one at a time and interventions used carry similar risks as with singletons so I won’t talk here about birth itself but more specifically about things that arise from birthing more than one baby at a time.
For decades women have been pressured into having epidurals for twins/multiples just in case the second baby needs help e.g. is breech or a caesarean is required. We know that epidurals carry risks of further intervention, especially with breech delivery because the mother cannot move and her hormones are no longer stimulated. Continuous foetal monitoring has been shown to increase the caesarean rate due to the woman being unable to move effectively. Continuous monitoring during twin births is standard hospital procedure so can we really trust any of the twin birth research to give us an accurate indication of what a woman is capable of?
In New Zealand you are within your legal rights to accept or refuse any care, to be treated respectfully, to ask for more information and to be given time to think about what you want to do. Unfortunately this is not common in the USA unless the woman is giving birth at home with midwives but that is only about 1%. Pressure is often put on parents of multiples by medical professionals as well as society to go with interventions and especially to induce at 38 weeks (if babies haven’t already arrived). It is up to the parents whether or not to go with ‘just in case obstetrics’ weighing up the pros and cons of doing so or to carry on with pregnancy, eating well and having extra visits to their LMC as the days and weeks go on and wait for birth to happen spontaneously.
During labour there will always be a midwife present as you come to full dilation. During the birth itself you may have a second midwife (or third if you’re at home) or if you’re in a hospital there will be one or more obstetricians. There will be paediatricians (one for each baby) on standby either in the room or just outside ready to look each baby over once they are born. You can choose whether or not to have any students present.
The second baby may take time to get into a good position and be born. This could be minutes or hours. It is extremely rare in the USA for an obstetrician to wait for the second twin if the first has been born. Unfortunately in America most are now cesareans anyway. So long as the mother is being looked after just like a singleton mother still in labour then she will have a great chance of birthing the second (third or fourth) baby naturally. Patience; that is the key.
If you are having a caesarean then all of these people will be in the operating theatre plus an anaesthetist, nurses for the operation and obviously your partner (unless you are under general anaesthetic). So there will be a minimum of nine people, maybe more.
Most birth centres won’t allow twin births as they screen women for the likelihood of a successful vaginal delivery. Since births of multiples is considered risky by the medical profession, birth centres have a just in case attitude. However, if you don’t feel safe birthing at hospital and you’re all healthy it is possible to find a confident and experienced midwife to support you with a homebirth. Ideally you will live near a hospital. Since the place with the most twin births in the world is a small village in Nigeria with a very under equipped hospital, I would say you’re good to plan for staying at home.
Remember… each baby comes out one at a time. What is required for a natural birth of singletons is also required for a natural birth of multiples.
The twins/ super twins came into the world together and I firmly believe they should stay together. Parents can talk with the NICU (neonatal intensive care unit) staff about keeping babies in the same incubator/open air crib.
A premature baby hasn’t got developed heat regulating systems yet and they are prone to breathing problems and heart rate issues. The monitors that inform staff of deviations can be quite loud and startle a new born causing the problems they are trying to monitor. You can ask that conversations, monitors and alarms to be as quiet as possible.
Kangaroo care is the term given to the care of a new born baby and their mother by keeping them close together with skin to skin contact and exclusive breastfeeding/ breast milk feeding with a tube, cup or spoon if the baby is unable to latch. Research shows…
“Results of two studies of the effects of 2 to 3 hours of kangaroo care (KC), one a randomized trial of 25 premature infants in open-air cribs and the other a pilot of 6 premature infants who were at least 24 hours postextubation, who were cared for in incubators are reviewed. Both studies incorporated a pre-test/post-test control group design. Heart rate and abdominal skin temperature rose for KC infants during KC. Heat loss did not occur during KC, and infants slept more during KC. Kangaroo care had a comforting effect on infants and their mothers. Apnoea and periodic breathing episodes dropped during KC for incubator infants.” 
Below are some tips on breastfeeding twins. If breastfeeding multiples you will find this even more relevant! Keep a stash of expressed breast milk (either your own or from a donor) in the freezer for times when more than two babies want feeding at once. Exclusively breastfeeding triplets is possible but you will need someone to help look after you (making you food, helping with burping and changing babies).
Get everyone on board. If you want to breastfeed twins or more you need the support of the people around you. You need to work on this before the babies are born and arrange for a lactation consultant to visit you regularly in the first few weeks.
“You don’t need to worry about not having enough milk. The more your babies suck and empty your breasts the more milk your breasts will produce. You might need to do some breastfeeding and pumping for the first couple of weeks just to get your milk supply up.
- Breastfeeding twins together will leave you with more time for yourself! A baby feeding schedule isn’t always possible with two babies that have different needs.
- Get yourself a comfortable twin nursing pillow before the birth to take to the hospital with you. A good breastfeeding pillow can ease allot of the stress, because you won’t still have to struggle with getting comfortable.
- Be prepared to breastfeed often! Keep in mind that it gets easier as time goes by
- Get together with other women who have successfully breastfed twins. Pick up some hints, ideas and advice
- Do not assign your babies to their own breasts; rather keep putting them on the opposite breast every time you feed. If you do this, you won’t have one breast becoming bigger than the other due to them having their own sucking patterns.” 
Get as much support as possible! Organise your support system long before babies are born. Make lots of homemade frozen meals to eat for the first few weeks after your babies are born. Ask all friends and family that visit to help with the house work and other children you may have. Do not be ashamed to ask people to bring a meal with them for your family that evening. It will take time to get into a routine with more than one baby and the routine may change every few weeks as their needs develop.
Remember that even with one new born the sleep deprivation and demands on your attention are very exhausting. Be kind to yourself. When the babies are older they will play with each other which in some ways makes it easier than having just one baby.
Relevant support groups and resources in New Zealand
Breastfeeding Twins: www.breastfeedingtwins.org
La Leche League: www.lalecheleague.org.nz
Multiple Birth Club New Zealand: www.multiples.org.nz
Twins & Multiple Births Association (UK) www.tamba.org.uk
I know you’ve been thinking about writing this for a long time and here it is! Congratulations. I loved reading it and you did an excellent job. Thank you.
 Elizabeth Nobel, Having Twins & More p. 32
 Elizabeth Nobel, Having Twins & More p. 30
 Elizabeth Nobel, Having Twins & More p. 166-168
 Elizabeth Nobel, Having Twins & More p. 113
 Elizabeth Nobel, Having Twins & More p. 438
 Elizabeth Nobel, Having Twins & More p. 438