Pregnancy is the period of gestation from the fertilization of an egg, through development of a fetus, and ending at birth.
Fertilization occurs when a sperm and an egg have fused together to form a zygote, which begins to divide as it moves towards the uterus.
The process of cleavage is the step of embryogenesis where the zygote divides to produce a cluster of cells known as the morula.
The blastocyst forms early in embryonic development and has two layers that form the embryo and placenta.
Implantation is the very early stage of pregnancy at which the embryo adheres to the wall of the uterus and begins to form the placenta.
Trophoblasts are the outer layer of cells that provide nutrients to the embryo and form part of the placenta.
The floor of the amniotic cavity is formed by the embryonic disc.
The amnion contains the fluid that cushions and protects the fetus.
The yolk sac is vascularized and contributes nutrients to the embryo.
The sinusoids are capillaries that develop after implantation to allow the exchange of gas and nutrients with the mother.
The extra-embryonic coelom is a cavity that contains the chorion. It is located between Heuser's membrane and the trophoblast.
During gastrulation, the embryo develops three germ layers (endoderm, mesoderm, and ectoderm) that differentiate into distinct tissues.
Following gastrulation, the neurulation process develops the neural tube in the ectoderm, above the notochord of the mesoderm.
Somites develop from the paraxial mesoderm and participate in the facilitation of multiple developmental processes.
The circulatory system develops initially via vasculogenesis, with the arterial and venous systems developing from distinct embryonic areas.
In the placenta, chorionic villi develop to maximize surface-area contact with the maternal blood for nutrient and gas exchange.
The fourth week of gestation is characterized by the flexion of the superior portion of the neural tube to create the mesencephalon.
Weeks five to eight of gestation develops the major organs, including the circulatory, nervous, and gastrointestinal systems.
Prodromal labor, which includes the latent phase of labor, marks the initial stages of parturition.
Vaginal delivery childbirth has three distinct phases: dilation of the cervix, delivery of the infant, and delivery of the placenta.
Post birth, an infant's physiology must adapt to breathing independently, changes in blood flow and energy access, and a cold environment.
Lactation is the secretion of milk from specialized glands (mammary glands) to provide nourishment to offspring.
At the end of the 10th week of gestation, the fetal period begins.
A teratogen is a compound that permanently deforms the function or structure of a developing embryo or fetus.
Prenatal diagnosis is a way to screen a fetus for diseases and/or conditions that may increase its morbidity and/or mortality.
Women undergo many physical changes during pregnancy due to hormonal fluctuations and the need to accommodate a growing fetus.
Protein and carbohydrate metabolisms are affected during pregnancy and maternal insulin resistance can lead to gestational diabetes.
Maternal physiological changes in pregnancy are entirely normal and serve as adaptations to better accommodate embryonic/fetal development.
In the absence of complications, pregnant women should continue aerobic and strength training exercise for the duration of gestation.
An ectopic pregnancy is implantation and development of the embryo outside the uterus, typically in the fallopian tubes.
Anencephaly (absence of forebrain and neocortex) is a neural tube defect occurring during embryonic development.
Placenta previa is an obstetric complication in which the placenta is attached to the uterine wall close to or covering the cervix.
Pregnancy tests are assays measuring indicators of pregnancy found in urine and blood samples, e.g., human chorionic gonadotropin (hCG).
There are many forms of pregnancy-induced hypertension (increased arterial blood pressure after 20 weeks gestation), of varying severity.
Dystocia is an abnormal or difficult childbirth or labor that may be resolved by manipulation, forceps, suction, or by cesarean section.
Preterm birth causes infants to be at greater risk for complications, disabilities, and impaired growth.
Infertility, in both males and females, refers to the inability to contribute to conception.
Congenital disorders, conditions existing at birth that often develop during gestation, are generically grouped regardless of cause.
Down syndrome is a developmental disorder caused by trisomy 21, or the presence of an extra 21 chromosome.