Study design and participants
We did a single-blind, two-group, randomized controlled trial at a tertiary hospital in Hainan, China. The study was approved by the human research ethics committees of the Affiliated Hospital of Hainan Medical University.
Eligible women were between 18 and 34 years old, 35 and 36 weeks’ gestation with a singleton pregnancy, healthy fetus, planning to breastfeed. Exclusion criteria were any pregnancy complication, such as preterm labor, diabetes, polycystic ovarian syndrome and hypertension; severe postpartum complication, such as postpartum Bleeding; fetal growth restriction; gestational week<38 weeks of delivery; the neonatal maternal separation; newborn birth weight <2500g; shortened lingual frenulum.
Randomization was done by a computerized random number, and the random numbers were reordered. After reordering, 1~45 were assigned to the intervention group, 46~90 digits were allocated to the control group, participants were masked to block size and group allocation.
Women in the control group received standard care that included breastfeeding health education and guidance, as follows. (1) 28-34 weeks of gestation: benefits of breastfeeding, the importance of early contact and early sucking, breastfeeding posture method of deep inclusion. (2) 35 -37 weeks of gestation: benefits of colostrum, the size of the stomach capacity of the newborn, importance of breastfeeding on demand. (3) postpartum hospitalization: assist the mother and newborn to make early contact, suck, instruct the mother at the bed to correctly include the nipple and evaluate the effectiveness of sucking, emphasize to mothers and primary caregivers the importance of breastfeeding on demand. (4) Postpartum follow-up: follow-up of the problems or doubts of the parturient by telephone, and give guidance.
Women in the intervention group received standard care, as well as instructions on
hand expressing breast milk: (a) Before each hand expressing, women¢s hands were washed for 1 min with soap; (b) Place the thumb above the nipple and the index finger below the nipple forming a "C" shape on the edge of the areola(usually 2-3cm away behind the nipple). Using the power of the fingertips to squeeze gently toward the chest wall, then relax and repeat building up a rhythm; (c) From the first day of 37 weeks of gestation, women were encouraged to hand expressing breast milk three times a day for 10 min until admission to hospital to give birth; and (d) In the weekly follow-up visit, women were encouraged to hand expressing breast milk under the electronic fetal monitoring, to evaluate whether it is correctly master the method of hand expressing, and monitor the fetal heart rate and uterine contraction while hand expressing. Women should continue to hand expressing, unless electronic fetal monitoring indicated that fetal intrauterine anoxia. Besides, the researcher contacted them via phone or WeChat every day.
Demographic data (including maternal age, ethnicity, height, pre-pregnancy weight, education, family monthly income) were obtained by questionnaire at recruitment before randomization. and are filled in by the research subjects on the day of admission. obstetric and neonatal medical outcomes (including gestational age of the childbirth, the mode of delivery, the sex of the newborn, the birth weight) were abstracted from the medical record after delivery.
Breastfeeding self-efficacy which is the confidence in the ability to breastfeed and produce milk postpartum, was assessed by the breastfeeding self-efficacy scale at 37 weeks of gestation, 38 weeks of gestation and third day postpartum The scale contains two dimensions of skills and inner activity, a total of 30 items, using a Likert 5-point scale (1~5 points), a total score of 30~150 points, the higher the score, the higher the maternal confidence in breastfeeding. The Cronbach'S a coefficient of this scale is 0.93, and the split-half reliability coefficient is 0.91.
Time to Lactogenesis II was evaluated three times daily began at 24 h pp by mother's perception of the onset of lactation which is a valid public health indicator of lactogenesis stage II . The researcher evaluated the clinical symptoms of Lactogenesis II(i.e., breast fullness, swelling, leakage), and the time to Lactogenesis II was recorded to the nearest hour.
Exclusive breastfeeding rate was used to evaluate feeding methods during the first three days of life, according to the retrospective method within 24 hours. Exclusive breastfeeding indicates that the infant received only breast milk, allowing for vitamin/mineral drops and medications .
Data were gathered by reachers and entered into Excel for analysis. The data analysis was performed using the SPSS 22.0 software, A p-value of less than 0.05 was considered significant. Measurement data normality was expressed as mean ± SD, tested with t-test or repeated-measures analysis of variance. Data that did not pass the variance test were compared with a nonparametric two-tailed Mann–Whitney rank-sum test. The enumeration data were expressed as n (%)and compared between groups by the or Fisher exact test, as appropriate.