Table 4.
Evolution of risk and protective factors for low birthweight, 1982–2015
| Cohort |
||||
|---|---|---|---|---|
| 1982 | 1993 | 2004 | 2015 | |
| Family income <1 minimum wage | 21.7% | 18.5% | 21.0% | 12.7% |
| Not in marriage or union | 8.2% | 12.4% | 16.4% | 14.2% |
| Black or brown skin colour | 17.9% | 22.6% | 26.9% | 28.2% |
| Maternal age > = 35 years | 9.8% | 10.9% | 13.3% | 14.5% |
| Schooling <4 years | 33.0% | 27.9% | 15.4% | 9.2% |
| Maternal height <150 cm | 10.9% | 4.5% | 6.9% | 2.5% |
| BMI <18.5 kg/m2 | 6.6% | 8.6% | 5.0% | 3.7% |
| BMI > = 30 kg/m2 | 3.7% | 4.6% | 6.1% | 18.4% |
| Smoking during pregnancy | 35.6% | 33.2% | 27.6% | 16.6% |
| Primiparity | 39.6% | 35.3% | 39.7% | 49.4% |
| Parity 2 or greater | 16.1% | 19.4% | 18.3% | 8.5% |
| Birth interval <24 months | 18.8% | 11.2% | 8.6% | 5.8% |
| Antenatal care <4 visits | 15.8% | 11.6% | 6.9% | 5.6% |
| Report of gestational diabetesa | 0.3% | 2.8% | 2.9% | 8.6% |
| Report of hypertension in pregnancya | 5.3% | 15.7% | 23.7% | 25.2% |
a
Due to changes in diagnostic criteria and in data collection methods, and to lower number of antenatal care visits for diagnosis of these conditions, the prevalence of diabetes and hypertension in the earlier cohorts was likely underestimated.