Article Text
PDFPoster presentations – Maternal medicine
Maternal age, fertility treatment, and the temporal effect on the twinning rate in Cardiff and Vale of Glamorgan (1980–2004)
Abstract
Objective Estimate the influence of maternal age, fertility treatment and period of delivery (temporal effect) on twin maternities
| Unadjusted | Adjusted | ||||||
|---|---|---|---|---|---|---|---|
| Period: | No (twin/total) | OR | 95% CI | p Value | OR | 95% CI | p Value |
| 1980–1984* | 284/27702 | 1 | 1 | ||||
| 1985–1989** | 139/12890 | 1.05 | 0.8, 1.2 | 0.62 | 1.03 | 0.84, 1.26 | 0.7 |
| 1990–1994 | 425/30530 | 1.3 | 1.1, 1.5 | < 0.0001 | 1.3 | 1.1, 1.5 | 0.001 |
| 1995–1999 | 484/28497 | 1.6 | 1.4, 1.9 | < 0.0001 | 1.5 | 1.3, 1.7 | < 0.0001 |
| 2000–2004 | 425/24777 | 1.6 | 1.4, 1.9 | < 0.0001 | 1.7 | 1.4, 1.9 | < 0.0001 |
| Age group | |||||||
| 25–29* | 507/38788 | 1 | 1 | ||||
| 15–19 | 60/11026 | 0.4 | 0.3, 0.5 | < 0.0001 | 0.4 | 0.3, 0.6 | < 0.0001 |
| 20–24 | 332/29933 | 0.8 | 0.7, 0.9 | 0.019 | 0.9 | 0.8, 1.06 | 0.3 |
| 30–34 | 557/30481 | 1.4 | 1.2, 1.5 | < 0.0001 | 1.2 | 1.08, 1.3 | 0.001 |
| 35–39 | 267/12107 | 1.7 | 1.4, 1.9 | < 0.0001 | 1.3 | 1.1, 1.5 | < 0.0001 |
| 40–45 | 34/2061 | 1.2 | 0.8, 1.7 | 0.18 | 0.9 | 0.6, 1.3 | 0.7 |
| Fertility treatment | |||||||
| No | 1440/119268 | 1 | 1 | ||||
| Yes | 317/5128 | 5.4 | 4.7, 6.1 | < 0.0001 | 4.8 | 4.2, 5.5 | <0.0001 |
Methods The authors performed an age period cohort analysis. A logistic regression model was used to assess the independent effect of each factor on twinning.
Results The following table summaries the odds of twinning by maternity periods, maternal age and fertility treatment:
Conclusion Our analysis confirms the importance of maternal age and fertility treatments on twin maternities. It also suggests a temporal effect, which may reflect recent changes in the environment surrounding pregnancy (nurture).