AbortionAbortion is the termination of a pregnancy by removal or expulsion of an embryo or fetus. An abortion that occurs without intervention is known as a miscarriage or "spontaneous abortion"; these occur in approximately 30% to 40% of all pregnancies. When deliberate steps are taken to end a pregnancy, it is called an induced abortion, or less frequently "induced miscarriage". The unmodified word abortion generally refers to an induced abortion. The reasons why women have abortions are diverse and vary across the world.
Ovarian follicleAn ovarian follicle is a roughly spheroid cellular aggregation set found in the ovaries. It secretes hormones that influence stages of the menstrual cycle. At the time of puberty, women have approximately 200,000 to 300,000 follicles, each with the potential to release an egg cell (ovum) at ovulation for fertilization. These eggs are developed once every menstrual cycle with around 450–500 being ovulated during a woman's reproductive lifetime. Ovarian follicles are the basic units of female reproductive biology.
TwinTwins are two offspring produced by the same pregnancy. Twins can be either monozygotic ('identical'), meaning that they develop from one zygote, which splits and forms two embryos, or dizygotic ('non-identical' or 'fraternal'), meaning that each twin develops from a separate egg and each egg is fertilized by its own sperm cell. Since identical twins develop from one zygote, they will share the same sex, while fraternal twins may or may not. In rare cases twins can have the same mother and different fathers (heteropaternal superfecundation).
Multiple birthA multiple birth is the culmination of one multiple pregnancy, wherein the mother gives birth to two or more babies. A term most applicable to vertebrate species, multiple births occur in most kinds of mammals, with varying frequencies. Such births are often named according to the number of offspring, as in twins and triplets. In non-humans, the whole group may also be referred to as a litter, and multiple births may be more common than single births. Multiple births in humans are the exception and can be exceptionally rare in the largest mammals.
Mother] A mother is the female parent of a child. A woman may be considered a mother by virtue of having given birth, by raising a child who may or may not be her biological offspring, or by supplying her ovum for fertilisation in the case of gestational surrogacy. A biological mother is the female genetic contributor to the creation of the infant, through sexual intercourse or egg donation. A biological mother may have legal obligations to a child not raised by her, such as an obligation of monetary support.
ChildbirthChildbirth, also known as labour, parturition and delivery, is the completion of pregnancy where one or more babies exits the internal environment of the mother via vaginal delivery or caesarean section. In 2019, there were about 140.11 million human births globally. In the developed countries, most deliveries occur in hospitals, while in the developing countries most are home births. The most common childbirth method worldwide is vaginal delivery.
Menstrual cycleThe menstrual cycle is a series of natural changes in hormone production and the structures of the uterus and ovaries of the female reproductive system that makes pregnancy possible. The ovarian cycle controls the production and release of eggs and the cyclic release of estrogen and progesterone. The uterine cycle governs the preparation and maintenance of the lining of the uterus (womb) to receive an embryo. These cycles are concurrent and coordinated, normally last between 21 and 35 days, with a median length of 28 days, and continue for about 30–45 years.
Placenta praeviaPlacenta praevia is when the placenta attaches inside the uterus but in a position near or over the cervical opening. Symptoms include vaginal bleeding in the second half of pregnancy. The bleeding is bright red and tends not to be associated with pain. Complications may include placenta accreta, dangerously low blood pressure, or bleeding after delivery. Complications for the baby may include fetal growth restriction. Risk factors include pregnancy at an older age and smoking as well as prior cesarean section, labor induction, or termination of pregnancy.
Gestational hypertensionGestational hypertension or pregnancy-induced hypertension (PIH) is the development of new hypertension in a pregnant woman after 20 weeks' gestation without the presence of protein in the urine or other signs of pre-eclampsia. Gestational hypertension is defined as having a blood pressure greater than 140/90 on two occasions at least 6 hours apart. No single diagnostic test currently exists to predict the likelihood of developing gestational hypertension. High blood pressure is the major sign in diagnosing gestational hypertension.
PlacentaThe placenta (: placentas or placentae) is a temporary embryonic and later fetal organ that begins developing from the blastocyst shortly after implantation. It plays critical roles in facilitating nutrient, gas and waste exchange between the physically separate maternal and fetal circulations, and is an important endocrine organ, producing hormones that regulate both maternal and fetal physiology during pregnancy. The placenta connects to the fetus via the umbilical cord, and on the opposite aspect to the maternal uterus in a species-dependent manner.
