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Oxytocin is a peptide hormone and neuropeptide normally produced in the hypothalamus and released by the posterior pituitary. [4] Present in animals since early stages of evolution, in humans it plays roles in behavior that include social bonding, love, reproduction, childbirth, and the period after childbirth.
During pregnancy, the syncytiotrophoblast cells of the placenta produce a polypeptide hormone, human placental lactogen (hPL), also known as human chorionic somatomammotropin (hCS). [ 17 ] in six weeks of gestation , production of hPL in maternal plasma is detected, then the concentration of hPL keeps increasing until week 30 of pregnancy. [ 17 ]
The yolk sac is the first element seen within the gestational sac during pregnancy, [1] usually at three days gestation. The yolk sac is situated on the front ( ventral ) part of the embryo ; it is lined by extra-embryonic endoderm , [ 3 ] outside of which is a layer of extra-embryonic mesenchyme , derived from the epiblast.
Different terms are used to describe prenatal development, meaning development before birth. A term with the same meaning is the "antepartum" (from Latin ante "before" and parere "to give birth") Sometimes "antepartum" is however used to denote the period between the 24th/26th week of gestational age until birth, for example in antepartum ...
Distress levels vary widely during pregnancy as well as during labour and delivery. They appear to be influenced by fear and anxiety levels, experience with prior childbirth, cultural ideas of childbirth pain, mobility during labour, and the support received during labour. [173] [174]
The amniotic sac, also called the bag of waters [1] [2] or the membranes, [3] is the sac in which the embryo and later fetus develops in amniotes.It is a thin but tough transparent pair of membranes that hold a developing embryo (and later fetus) until shortly before birth.
Decidualization is a process that results in significant changes to cells of the endometrium in preparation for, and during, pregnancy. This includes morphological and functional changes (the decidual reaction) to endometrial stromal cells (ESCs), the presence of decidual white blood cells (leukocytes), and vascular changes to maternal arteries.
In placental mammals, the umbilical cord (also called the navel string, [1] birth cord or funiculus umbilicalis) is a conduit between the developing embryo or fetus and the placenta. During prenatal development , the umbilical cord is physiologically and genetically part of the fetus and (in humans) normally contains two arteries (the umbilical ...