Weight gain during pregnancy: Does the antenatal care provider make a difference? A retrospective cohort study

Abstract

Background: The primary aim of this study was to examine weight gain during pregnancy and associated adverse outcomes across different types of antenatal health care providers. Our research question examined whether type of antenatal health care provider (family physician, obstetrician, midwife, or family physician plus obstetrician) was associated with differing rates of excess or inadequate weight gain and associated adverse outcomes including being large for gestational age, being small for gestational age, cesarean delivery and preterm birth.

Methods: This retrospective cohort study used data from the Better Outcomes Registry & Network Information System, 2014-2016, for singleton hospital births at 20-42 weeks' gestation in Ontario. We calculated descriptive statistics to summarize patient characteristics and outcomes by antenatal health care provider. We calculated crude and adjusted relative risks with 95% confidence intervals (CIs) for the exposure (weight gain during pregnancy) relative to each secondary outcome by health care provider. We calculated population attributable fractions with 95% CIs to assess the proportion of secondary outcomes that could be prevented if inadequate or excess weight gain (according to the 2009 Institute of Medicine guidelines) were removed by health care provider.

Results: The final cohort consisted of 231 697 pregnancies, of which 26 043 (11.2%), 136 994 (59.1%), 32 262 (13.9%) and 36 298 (15.7%) were managed by a family physician, obstetrician, midwife, and family physician plus obstetrician, respectively. Rates of weight gain below, within or above recommended levels were 31 742 (13.7%), 71 826 (31.0%) and 128 128 (55.3%), respectively, and did not differ across health care provider groups. No difference was observed in rates of secondary outcomes according to weight gain across health care providers. Excess weight gain was associated with a significant risk of being large for gestational age and cesarean delivery, and inadequate weight gain was associated with an increased risk of being small for gestational age and preterm birth. The population attributable fractions indicated a pronounced contribution of excess weight gain to being large for gestational age across all health care provider groups.

Interpretation: Weight gain during pregnancy and rates of associated secondary outcomes did not differ according to antenatal health care provider. This suggests a need for further research exploring counselling techniques and strategies for all types of antenatal health care providers to use in order to promote optimal weight gain during pregnancy.

Figure 1:

Flow chart showing cohort selection. Note: BMI = body mass index.

Figure 2:

Proportions of pregnancies with weight gain below, within and above recommended levels, by antenatal health care provider.

Figure 3:

Adjusted relative risk (RR) of being small for gestational age, being large for gestational age, preterm birth and cesarean delivery among pregnancies with a weight below that recommended relative to those with a weight gain within recommended levels, stratified according to antenatal health care provider. Note: CI = confidence interval. *Adjusted for maternal age, parity, gestational age at birth, prepregnancy body mass index (BMI), income quintile, education quintile, smoking, depression, preexisting diabetes, preexisting hypertension and gestational diabetes mellitus. †Adjusted for maternal age, parity, gestational age at birth, prepregnancy BMI, income quintile, education quintile, smoking, preexisting diabetes, preexisting hypertension, gestational diabetes, drug exposure, alcohol consumption, mental illness, previous cesarean delivery, previous term birth, previous preterm birth, previous vaginal birth, previous stillbirth, previous abortion, nonvertex presentation and male infant.

Figure 4:

Adjusted relative risk (RR) of being small for gestational age, being large for gestational age, preterm birth and cesarean delivery among pregnancies with a weight gain above that recommended relative to those with a weight gain within recommended levels, stratified according to antenatal health care provider. Note: CI = confidence interval. *Adjusted for maternal age, parity, gestational age at birth, prepregnancy body mass index (BMI), income quintile, education quintile, smoking, depression, preexisting diabetes, preexisting hypertension and gestational diabetes mellitus. †Adjusted for maternal age, parity, gestational age at birth, prepregnancy BMI, income quintile, education quintile, smoking, preexisting diabetes, preexisting hypertension, gestational diabetes, drug exposure, alcohol consumption, mental illness, previous cesarean delivery, previous term birth, previous preterm birth, previous vaginal birth, previous stillbirth, previous abortion, nonvertex presentation and male infant.

Figure 5:

Population attributable fractions of being small for gestational age, being large for gestational age, preterm birth and cesarean delivery for weight gain above that recommended relative to weight gain within recommended levels, stratified according to antenatal health care provider. Note: CI = confidence interval, RR = relative risk.

Figure 6:

Population attributable fractions of being small for gestational age, being large for gestational age, preterm birth and cesarean delivery for weight gain below that recommended relative to weight gain within recommended levels, stratified according to antenatal health care provider. Note: CI = confidence interval, RR = relative risk.