Association Of Gestational Weight Gain With Onset Of Lactogenesis And Breastfeeding Practices: A Cohort Study

Objectives:Breast milk is the most optimal food for infants,and breastfeeding has many established health benefits to both babies and mothers.Lactogenesis is considered as a physiological phenomenon,which is important for breastfeeding successfully.The perception of onset of lactogenesis?OL?more than 72 hours postpartum is considered delayed OL.A few researches of delayed OL,the association between delayed OL and breastfeeding practices were conducted as far as we know,and the results were inconsistent.We aimed:?1?To explore the prevalence of delayed OL and examine the association of gestational weigh gain?GWG?and delayed OL.?2?To examine the association of GWG and delayed OL with full breastfeeding?FBF?,any breastfeeding?ABF?,and the duration of ABF.?3?To examine the association of GWG and delayed OL with postpartum weight retention?PPWR?.Population and methods:Participants in the present study were all from the Tongji Maternal and Child Health Cohort?TMCHC?.We obtained data on demographic characteristics and the pre-pregnancy weight of pregnant women at the enrolment before the 16 weeks of gestational.We also measure the initial weight and height at the enrolment,which was used to calculated pre-pregnancy body mass index?BMI?.The last weight measurement?LWM?was assessed before delivery.Information on delivery and neonatal outcomes were obtained from hospital medical records.The postpartum weight was assessed at day 1postpartum.Information on in-hospital breastfeeding for each mother-infant dyad was obtained by using a LATCH breastfeeding assessment tool at day 1 postpartum face-to-face interviews.To describes the ability of the infant to latch onto the breast and audible swallowing noted at the breast,the type of nipples and the comfort level of the mother regarding her breast,and the amount of help the mother require to position her baby at the breast.At the day 1 postpartum face-to-face interviews,participants were asked to describe the first time they felt their breasts were noticeably fuller than they were before giving birth.We repeated these interview questions with day 3 postpartum if the women did not feel their breasts fuller in the previous visit.Breastfeeding practices and postpartum weight were collected at 3,6 and 12 months postpartum by telephone interview.?1?GWG was assessed by the LWM and the self-reported pre-pregnancy weight at enrolment.GWG was categorized in quartiles?Q1,Q2,Q3,Q4?according to different pre-pregnancy BMI groups.We used Generalized Estimated Equation?GEE?analysis to examine the association between GWG and delayed OL.GWG was also classified as inadequate,adequate,and excessive according to the 2009 Institute of Medicine?IOM?guidelines.We used GEE analysis to examine the association between GWG and delayed OL.?2?Breastfeeding practices were classified as FBF,which was defined as breastfeeding but water and tea without sugar are allowed).GEE analysis was used to examine the association of GWG and delayed OL with FBF at 3 month postpartum,6month postpartum.Breastfeeding practices were classified as ABF,which was defined as receiving any breast milk,including FBF and mixed breastfeeding.GEE analysis was used to examine the association of GWG and delayed OL with ABF at 3 month postpartum,6 month postpartum.Kaplan-Meier Curve and Cox regression were used to examine the association of GWG and delayed OL with the duration of ABF.?3?PPWR was assessed by the postpartum weight at 12 months postpartum and the self-reported pre-pregnancy weight at enrolment.And PPWR?5kg was identified as excessive PPWR.Multivariate logistic regression was used to examine the association of GWG and delayed OL with PPWR.We also used GEE analysis to explore the association of GWG and delayed OL with excessive PPWR.Results:?1?The mean age of 3282 participants was?28.3±3.4?years old,mean pre-pregnancy BMI was?20.8±2.6?kg/m²,97.5%of participants were Han Chinese,60.5%of participants with the college education level and above,83.8%of them were Primiparous,and delayed OL was reported by 18.4%?604/3282?of the participants.After adjusting for maternal age,ethnicity,education,income,parity,pre-pregnancy BMI,GDM,gestational age,birth weight and LATCH-score,compared to the lowest Q1 of GWG,Q3 and Q4 was associated with a significant higher risk of delayed OL,the RRs?95%CIs?were 1.36?1.09,1.69?and 1.32?1.05,1.65?.When GWG was classified by the 2009 IOM guidelines,after adjustment for potential confounders,compared with women with adequate GWG,inadequate GWG and excessive GWG were not significantly associated with risk of delayed?P>0.05?,the RRs?95%CIs?were 0.85?0.66,1.09?and 1.10?0.94,1.30?.?2?Among 2877 participants who had breastfeeding information,the rates of FBF at 3,6 month were 62.1%?45.1%;the rates of ABF at 3,6,12 month were 89.1%,78.5%,35.0%.After adjusting for maternal age,ethnicity,education,income,parity,pre-pregnancy BMI,GDM,GWG,gestational age,birth weight and LATCH-score,when compared with timely OL,delayed OL was significantly associated with higher risk of inability to sustain FBF at 3 month postpartum?RR:1.26,95%CI:1.12,1.42?and 6 month postpartum?RR:1.15,95%CI:1.06,1.26?.Delayed OL was also significantly associated with early termination of ABF?HR:1.16,95%CI:1.03,1.32?in adjusted model.Delayed OL was not significantly associated with ABF at 3 month postpartum and 6 month postpartum,the RRs?95%CIs?were 1.14?0.86,1.51?and 1.17?0.97,1.40?,respectively.After adjusting for maternal age,ethnicity,education,income,parity,pre-pregnancy BMI,GDM,gestational age,birth weight,LATCH-score and OL status,compared to Q1 of GWG,Q3 was significantly associated with termination of ABF?HR:1.17,95%CI:1.01,1.36?,Q4 was significantly associated with termination of ABF?HR:1.16,95%CI:1.03,1.32?.After adjusting for potential confounders,compared to Q1 of GWG,Q3 and Q4 were not significantly associated with ABF,FBF at 3,6 month postpartum,In a combined analysis,GWG was categorized in two groups according to median(P₅₀).When compared with women had lower GWG(<P₅₀)and timely OL,those with higher GWG(?P₅₀)and subsequently experienced delayed OL was associated with termination of ABF?adjusted HR:1.34,95%CI:1.14,1.59?.?3?Of 2261 participants who had postpartum weight information,mean PPWR at12 month postpartum was?2.4±3.9?kg,26.5%?599/2261?were experienced excessive PPWR.After adjusting for maternal age,ethnicity,education,income,parity,pre-pregnancy BMI,GDM,OL status,exercise,and breastfeeding duration,compared to Q1 of GWG,the PPWR were increased by 1.00 kg?95%CI:0.56,1.45?for Q2,1.94 kg?95%CI:1.49,2.38?for Q3,and 3.45 kg?95%CI:2.99,3.90?for Q4.After adjusting for potential confounders,compared to Q1 of GWG,RRs?95%CIs?for the risk of excessive PPWR were 1.58?1.17,2.14?for Q2,2.05?1.53,2.75?for Q3,and 3.28?2.48,4.33?for Q4.After adjusting for maternal age,ethnicity,education,income,parity,pre-pregnancy BMI,GDM,GWG,exercise,and breastfeeding duration,the difference of PPWR between timely OL and delayed OL was not statistically significant?P>0.05?,the difference of risk of excessive PPWR was also not statistically significant?P>0.05?.Conclusions:?1?Delayed OL was reported by 18.4%among Chinese participants.Women whose pre-pregnancy BMI<24.0 kg/m² with GWG?16.0 kg,or pre-pregnancy BMI?24.0 kg/m² with GWG?15.0 kg were more likely experienced delayed OL,and have a higher risk of termination of ABF.?2?Delayed OL was not only associated with lower rates of FBF at 3 month and 6month postpartum,but also associated with a lower rate of ABF during 12 months postpartum.?3?Compared with women whose pre-pregnancy BMI<24.0 kg/m² with GWG<13.5 kg,18.5?pre-pregnancy BMI<24.0 kg/m² with GWG<13.0 kg,or pre-pregnancy BMI?24.0 kg/m² with GWG<10.8 kg,women with higher GWG were more likely to have higher PPWR at 12 month postpartum and higher risk of excessive PPWR.