Cervix dilation and breaking water happen twelve hours before birth {birth, reproduction}| {nativity}. Fetus comes out head first, with face toward spine, taking 20 to 60 minutes. After cutting umbilical cord, umbilical arteries and veins close. Carbon-dioxide buildup causes first breath to start. At birth, heart blood flow changes direction. Head pressure can cause brain blood-vessel hemorrhage, and little breathing and low oxygen are dangers.
Cervix dilation and amnion breaking {breaking water}| happen twelve hours before birth.
Fetus comes out {parturition}| head first, with face toward spine, taking 20 to 60 minutes.
Surgically removing baby from uterus {Caesarean}| can be necessary.
Placenta {afterbirth}| expulsion happens 15 minutes after birth.
If oval window fails to close, blood is low in oxygen {blue baby}|.
Baby hearts have an opening {oval window, heart} between atria.
Birth weight can be less than 2.5 kilograms {premature birth}.
Female animals can have more than one baby in litters {multiparous}.
Female mammals can have one child each sexual period {uniparous}.
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Date Modified: 2022.0225