Table 2.
Studies examining PRL in relation to maternal BMI and/or gestational weight gain – 5 studies.
| Author and year | Design | Participants and sample size | Methodology | PRL pregnancy timepoints | Metabolic parameters analysed in relation to PRL | Results | Authors’ conclusions | Risk of bias rating |
|---|---|---|---|---|---|---|---|---|
| Lagiou et al, 2006 (29) | Longitudinal observational | n=270, Caucasian only subset of the cohort of Xu et al. (below); PGDM excluded | PRL measured at 16 weeks and 27 weeks | 16 weeks 27 weeks |
Maternal BMI pre-preg Maternal GWG |
Maternal BMI pre-preg NS associated with either 16 or 27 wk PRL (after adjustment for key covariates). GWG NS associated with either 16 or 27 wk PRL (after adjustment for key covariates). |
No relationship between PRL at 16 or 27 weeks and either maternal pre-preg BMI or GWG. | High |
| Lappas et al, 2020 (30) | Cross sectional | n=69, all non-obese, none with PGDM or GDM | PRL measured at time of delivery | At time of elective Caesarean section | Maternal GWG | Excessive GWG group (n=35) had tendency to lower PRL than recommended GWG group (n=34): 159.5 ± 66.1 vs 194.0 ± 85.6 ng/mL, just NS (p=0.07). Est mean diff = -34.3 ng/mL, 95% CI (-71.3, 2.7). Each 1kg inc in GWG = -3.11 ng/mL PRL (95% CI -8.28, 2.07) |
Trend to lower PRL levels in those with excess GWG than recommended GWG (at term), although just short of sig. PRL known to stimulate appetite in preg and involved in leptin resistance, so trend lower PRL in excess GWG group deemed ‘surprising’. |
Moderate |
| Park et al, 2013 (25) | Cross sectional | n=215 GDM cases (98 lean, 117 overweight) n=531 non-GDM controls (395 lean, 136 overweight) |
One-off PRL sampling at 24-28 weeks | 24-28 weeks | Maternal BMI category (overweight defined as >23kg/m2), with stratification by GDM status |
Mean PRL levels by group (ng/mL): lean non-GDM = 138.2 ± 86.3 lean GDM = 146.3 ± 52.0 overweight non-GDM = 129.7 ± 56.8 overweight GDM = 129.0 ± 45.1 Sig diff between lean and overweight women (higher PRL in lean), but not between GDM/non-GDM groups. |
PRL at 24-28 weeks lower in overweight Korean women regardless of GDM status. | Low |
| Ren et al, 2022 (31) | Longitudinal observational | n=30 overweight/obese n=33 lean controls |
PRL sampled at 37 weeks of preg, (and again at 48h postpartum, see Table 3 ) | 37 weeks | Maternal pre-preg BMI category (overweight defined as >24 kg/m2) | Baseline PRL in ng/mL sig lower in overweight/obese women than lean control women at 37 weeks (overweight/obese = 231.80 ± 72.94 vs. lean = 304.29 ± 75.64; sig.) | PRL at 37 weeks lower in overweight/obese Chinese women than controls. | Low |
| Xu et al, 2003 (32) | Longitudinal observational | n=304 Caucasian (USA) and n=335 Chinese; PGDM excluded | PRL measured at 16 weeks and 27 weeks | 16 weeks 27 weeks |
Maternal BMI pre-preg Maternal GWG, adjusted for pre-preg BMI |
NS associated with PRL (both visits, adjusted for key covariates). NS associated with PRL (both visits, adjusted for key covariates). |
NS association between PRL and adjusted GWG, or between PRL and maternal pre-preg BMI. | Moderate |
PRL, prolactin; GDM, gestational diabetes mellitus; PGDM, pre-gestational diabetes mellitus; BMI, body mass index; GWG, gestational weight gain. Data are presented as mean ± SD unless otherwise specified in the table.