The necessity to specify paternities in all obstetrical files in multigravidae

To compare in singleton multiparous pregnancies the effect of having a new father for an index pregnancy as compared with multiparas with the same male partner and primiparas.

21 year data, 2001-2021, Reunion island. We compared 2233 multiparas who had a new partner NewPMP (cases) with 50,364 same partner multiparas samePMP (controls) and 30,741 primiparas. Paired t-test in for parametric, Mann-Whitney U test for non-parametric continuous variables. P-values < 0.05.

As compared with primiparas, New paternity multiparas had similar neonatal outcomes: average birthweights 3044 g and 3017 g (vs 3125 g grams SamePMP, p < 0.0001), rates of low birthweights, very low birthweights (< 1500 g), rate of prematurity < 37 weeks, rate of early prematurity < 33 weeks and also "placental " intrauterine growth retardation, IUGR. Both primiparas and NewPMP had significant worse neonatal outcomes as compared with same partner multiparas for all these same items (all p < 0.05)). NewPMP had a much higher risk of preeclampsia than primiparas and samePMP (respectively, OR 1.74 and 2.9, p < 0.001), fetal deaths and perinatal mortality respectively, OR 1.4 and 1.8, p < 0.001. In 4 logistical models (primiparity, primipaternity, preeclampsia and "placental IUGR") new paternity multiparas had similar results compared with primiparas but very different results when compared with same partner multiparas.

New paternity multiparas share with primiparas a significantly higher risk of perinatal and maternal morbidities than same partner multiparas. Paternity needs to be specified in all obstetrical files, perinatal databases- Health Registries.