Mean birth interval between second and third live births according to sex of third live birth, by maternal birthplace and sex of previous siblings
| Sex of 2 previous siblings | Mean birth interval between second and third live births, mo | Mean difference* (95% CI) | |
|---|---|---|---|
| Male third-born infant | Female third-born infant | ||
| Mothers born in Canada | |||
| MM | 40.2 | 40.5 | −0.2 (−0.8 to 0.3) |
| FF | 40.7 | 40.7 | 0.0 (−0.6 to 0.7) |
| MF or FM | 41.8 | 42.1 | −0.3 (−0.8 to 0.2) |
| Mothers born in India | |||
| MM | 45.4 | 47.9 | −2.4 (−7.4 to 2.6) |
| FF | 49.0 | 45.4 | 3.8 (0.9 to 6.7)† |
| MF or FM | 47.8 | 48.8 | −1.1 (−4.6 to 2.3) |
Note: CI = confidence interval, FF = both previous living siblings were female, MM = both previous living siblings were male.
↵* Mean difference = mean birth interval to third-born male – mean birth interval to third-born female. Adjusted for the number of spontaneous abortions between live births.
↵† p = 0.01.