HIDRATA Study: Efficacy of a Hydration Protocol in Nulliparous Women During Labor
HIDRATA Study: Efficacy of a Hydration Protocol in Nulliparous Women During Labor
Aim. To evaluate the efficacy of optimizing hydration during labor in nulliparous women with
 respect to reducing the duration of dilation and the second stage of labor, lowering the
 incidence of Cesarean sections and fever, and also with respect to changes in sodium and
 osmolarity in blood and urine, and 24 hour diuresis.

 Background. In the international scientific community there is a lack of consensus regarding
 the most suitable hydration strategies to be used in the attention of nulliparous women
 during low risk birth. Insufficient hydration during labor is associated with increased
 maternal and neonatal morbidity.

 Design. A randomized, controlled clinical trial with allocation concealment and masking
 during the evaluation of the results.

 Methods. A study of nulliparous women whose births and newborn are attended in the Obstetric
 Service of a University Hospital. The women will be randomized to two groups: the "optimal
 hydration" group, that will be guaranteed 300 ml/h (intravenous crystalloids and water) with
 a minimum diuresis of 400 ml/24h; and the "variability in hydration" group, comprised of the
 administration of intravenous and clear liquid volumes, without any established perfusion
 rate, based on criteria established by the healthcare professional attending the birth, and
 without established minimum diuresis. Mother outcomes: duration of labor, Cesarean section,
 fever, dehydration. Newborn outcomes: distress, hypoglycemia, hyponatremia, jaundice, weight
 loss in 48h, breastfeeding difficulties. Analysis will be per-protocol. Statistical
 significance will be set at p<0.05 Discussion. The findings obtained in this study will
 provide new evidence for considering the benefits of providing women with suitable optimized
 hydration during labor. Diminishing the clinical practice variability related to hydration
 strategies applied to nulliparous women attended during labor through the use of a
 decision-making algorithm to administer optimal hydration, would imply improved health and
 safety for mothers and their newborn together with reduced maternal and neonatal morbidity.

 Funding granted in 2015 by the Spanish Health Research Fund (PI 15/00897, Ministry of
 Health).

 Keywords: hydration; dehydration; adverse events; labor; Cesarean section, fever.
PRIMARY AIM:

 To evaluate the efficacy of "optimal hydration" during labor in nulliparous pregnant women
 attended for spontaneous or induced deliveries with respect to the reduction in dilation
 times, second stage of labor and total labor time.

 METHODOLOGY A randomized controlled clinical trial, with concealed allocation. The study is
 being carried out in a large university hospital belonging to the Spanish National Health
 System. The trial is being carried out in the Obstetrics Service in Hospital Universitario
 Puerta de Hierro Majadahonda, Madrid. All the study participants will be nulliparous women
 (women who have not given birth by the vaginal route), and their neonates, who are attended
 during either spontaneous labor (2-3 regular uterine contractions in 10 minutes, cervical
 effacement greater than 50% and 3-4 cm spontaneous dilatation) or induced labor (when labor
 is induced artificially). The sample size was estimated on the basis of cohorts previously
 studied by the same team of investigators in the same hospital which observed that women who
 had received liquid volumes of less than 300 ml/h during labor took a mean (SD) of 754 (251)
 minutes to complete the birth, whereas women who received a volume equal to or greater than
 300 ml/h took a mean (SD) of 592 (287) minutes. Assuming a 95% confidence interval, in a
 bilateral contrast, with a statistical power of 90%, a population of 59 is required for each
 group. In addition, a 10% increase is taken into account for those lost to follow-up.
 Therefore, the final sample size is 130, with 65 women in each group.

 Intervention group protocol: "optimal hydration" Women in this group will be attended by the
 13 investigation team midwives who have agreed to collaborate with the study's clinical team.
 Attention will include: (A) administration of a volume of liquids equal to 300 ml/h during
 labor which is defined as from the moment of admittance to the delivery room until the birth
 of the child; (B) more than 80% of the volume will be perfused intravenously using a
 physiological saline solution; (C) the women will be encouraged to drink clear liquids from
 the moment of admittance to the delivery room until reaching 10 cm dilation, such liquids
 will only be bottled mineral water (80%) and isotonic drinks (20%); (D) the perfusion rate
 will be increased if the woman has diuresis lower than 400 ml in 24h or presents temperature
 equal to or greater than 37.8ºC.

 Control group protocol: "variability in hydration" Women in this group will be attended by
 the 16 delivery room midwives who do not belong to the investigation team. The women will be
 hydrated in accordance with the midwives' experience, training and clinical criteria, either
 independently or jointly with the attending clinicians (obstetricians, gynecologists and
 anesthetists). The principal lines of attention will be: (A) administration of undetermined
 volumes of liquids during labor which is defined as from the moment of admittance to the
 delivery room until the birth of the child; (B) the volume will be perfused intravenously
 using physiological saline solution, Ringer's, 5% glucose, 10% glucose or voluven; (C) the
 women will be allowed to drink clear liquids at their own pace and to their liking from the
 moment of admittance to the delivery room until reaching 10 cm dilation, such liquids can be
 water and isotonic drinks; (D) changes in perfusion rate and diuresis or increases in
 temperature (higher then 37.7ºC) will not be evaluated.

 Study procedures The midwife in the Obstetric Emergency department will verify whether women
 attending the service comply with the criteria for inclusion in the study but do not present
 any exclusion criteria. In such cases, the midwife will give the woman verbal and written
 information about the study. If the woman is willing to participate, she will have to return
 a signed Informed Consent form to the midwife. The woman will at this moment be assigned the
 next consecutive number for inclusion in the study. The midwife will open the corresponding
 envelope containing the information regarding the group to which the woman has been assigned.
 In the case of assignment to the "controled hydration" group, the midwife responsible for her
 attention will be one of the 13 in the investigating team. If the woman is assigned to the
 "uncontroled in hydration" group, the midwife responsible for her attention will be one of
 the 16 who do not belong to the investigating team.

 Study measures

 Maternal variables:

 -  Main Outcomes: duration of dilation, duration of second stage of labor, and total
 duration from onset of labor until the birth.

 -  Secondary Outcomes: times on oxytocin, with ruptured membrane and epidural anesthesia,
 incidence of Cesarean section, incidence of intrapartum fever (temperature equal to or
 higher than 38ºC) and postpartum fever, dehydration (diuresis lower than 400 ml in 24 h,
 osmolarity concentration in urine/blood, sodium in urine/blood), headaches, nausea,
 vomiting, confusional state, hyperglycemia (blood sugar higher than 120 mg/dl),
 difficulty establishing breastfeeding, badly controlled thirst, badly controlled pain.

 -  Sociodemographic variables: age, nationality, educational level.

 -  Clinical variables on admittance, intrapartum, immediate postpartum (first 2 hours) and
 intermediate postpartum period (24 and 48 hours).

 Neonate variables:

 -  Neonate outcomes: distress, seizures, nausea, vomiting, tachypnea, hypoglycemia
 (glycemia lower than 40 ml/dl), hyponatremia (sodium in umbilical cord blood <130
 mEq/L), fever (temperature equal to or higher than 38ºC), jaundice (requiring
 phototherapy), more than 7% weight loss in 48 h, difficulty initiating breast feeding.

 -  Variables related to the newborn child (from birth, at 24 and 48 h): ions (sodium,
 potassium and glucose) in umbilical cord blood, gender, weight (at birth, at 24 and 48
 h), distress, temperature, desire to suckle, colostrum, initiation of breastfeeding,
 type of breastfeeding, jaundice and capillary bilirubin levels (24 and 48 h).

 Data collection Information will be collected from: clinical histories, partogram,
 observation, physical examination, fetal monitoring, scales (adult and newborn), analytical
 values, vital signs, visual analogue scale for pain (from 0 to 10), sensation of nausea (from
 0 to 5), sensation of thirst (from 0 to 10), Armstrong scale (dehydration evaluation),
 Bilitest (capillary bilirubin levels), Silverman test (respiratory distress at birth).
 Maternal laboratory values: antenatal and in the immediate postpartum. Requests for blood and
 urine samples and their extraction, together with all other analyses, will be carried out by
 the Emergency Obstetric Service midwife according to normal clinical practice. Neonate
 laboratory values: at the time of birth. Requests for analyses will be made by the midwife
 during the dilation phase. Taking advantage of the moment when other samples are taken
 according to normal clinical practice (umbilical cord pH and blood group), sample extractions
 will be carried out by the midwife or obstetrician attending the delivery. The midwife will
 be responsible for weighing the newborn in the delivery room and in the Obstetric Service
 ward. The variables corresponding to the immediate postpartum (24-48 h) will be recorded by
 ward nurses who will be blinded to the group assignments.

 Data analysis Analyses will be carries by assigned treatment and by intention to treat. Mean
 differences will be presented for qualitative values, and relative risks, reductions of
 relative and absolute risk, and the number required to treat for qualitative variables. All
 variables will be shown with their 95% confidence interval. Statistical significance will be
 set at p<0.05.
Inclusion Criteria: Women who:

 -  Are 18 years-of-age or older;

 -  With gestation between 37-41+3 weeks

 -  Have signed an informed consent form.

 Exclusion Criteria: The following exclusion criteria will apply:

 -  Women who do not have sufficient understanding of the Spanish language or those with
 whom communication will be difficult

 -  Women with a multiple gestation

 -  Gestation with high maternal or neonatal risk

 -  Maternal pathology (metabolic diseases, preeclampsia, eclampsia, etc.)

 -  Fetal pathology

 -  Precipitated delivery; fetal death.

 Criteria for leaving the study:

 -  Severe maternal complications during the immediate or intermediate postpartum periods
 that require admittance to the Intensive care Unit

 -  Neonatal complications that require admittance to the Neonatology Service for more
 than 48 hours

 -  If, once the study has started, the participant fails to cooperate during follow-up
 (delivery, during the immediate or intermediate postpartum periods) or decides to
 discontinue their participation.