Table 3.

Included studies on maternal obesity and delayed onset of lactation

Authors, Year of Publication, Country, and Year(s) of Study	Participants	Definition of obesity	Results
Chapman & Perez-Escamilla 1999 [15] USA 1996–1997	Hartford Hospital, Connecticut Healthy, single, term infant n = 192	Women's bodies were classified as slim, average, heavy or obese	Delayed lactogenesis (> 72 hours) Slim/average build 26.4% Heavy/obese build 52.2% Multivariate analysis Heavy/obese build OR 3.2 (95 CI% 1.5, 6.7) (adjusted for birth weight, method of birth, ethnicity, serious medical condition, parity, formula feeding day 2)
Chapman & Perez-Escamilla 2000 [46] USA 1997–1998	Connecticut Healthy mothers with a healthy, single, term infant n = 57	Definition of obesity: at least 2 of 3: 1. BMI at 72 h > 30, 2. subscapular skin fold thickness at 72 h > 33.7 mm (> 85%ile) 3. heavy/obese build on day 1.	Multivariate analysis Onset -Milk transfer at 60 h (< or > 9.2 g/feed) Obese: OR 6.14 (95%CI: 1.10, 37.41, p = 0.05) compared to non-obese Onset – Maternal perception (< or > 72 h) Obese: OR 1.97 (95%CI: 0.29, 13.41, p = 0.49) compared to non-obese Non-obese: Women who bf more frequently had higher milk transfer values and earlier onset of lactogenesis, than women who bf less frequently Obese: No relationship between these variables
Dewey et al 2003 [47] USA 1999	Davis, California Healthy, single, term infants, planning to bf > 1 m n = 280	BMI measured 2 weeks postpartum BMI > 27.0 taken as overweight/obese	Delayed lactogenesis (> 72 hours) Normal 16% Overweight/obese 33% p < 0.05 Multivariate analysis for delayed lactogenesis: Overweight/obese: RR 2.46 (95%CI: 1.45, 3.64) (adjusted for C-section, parity, flat nipples, birth weight): Multivariate analysis for suboptimal infant feeding behaviour on day 7: Overweight/obese: RR 2.58 (95%CI: 1.07, 5.22).
Hilson et al 2004 [42] USA 1998	Bassett Hospital, Cooperstown, NY Intended to bf, singleton infant n = 114	BMI calculated from pre-pregnancy weight and height IOM definition of obesity	Delayed lactogenesis (> 72 hours) Normal 18.5% Overweight 30.8% Obese 33.3% Univariate analysis NS Multivariate analysis NS {not enough power to show a difference}
Rasmussen et al 2004 [16] USA Years of study not stated	Bassett Healthcare, Cooperstown, NY n = 40	Pre-pregnancy BMI from medical records IOM definition of obesity	Duration of feed at 7 days postpartum: Overweight/obese women: infants fed for longer: 23.2 (sd 5.6) mins, compared to 15.3 (sd 6.1) mins for normal weight women (p < 0.005) Prolactin response to suckling (ng/ml): 48 hours Normal women 26.0 (sd 61.5) Overweight/obese women -10.3 (sd 28.3) p < 0.05 Prolactin response to suckling (ng/ml): 7 days Normal women 80.9 (sd 67.6) Overweight/obese women 57.1 (sd 60.2) NS Other hormones (insulin, estradiol, progesterone): NS difference between groups. However, insulin levels were 44% higher in overweight/obese women at 7 days (non-fasting levels and inadequate power). Path analysis: effect of pre-pregnant BMI on prolactin response at 7 days: -30.9 ng/ml.