妊娠-科普123

妊娠

杂烩百科2023-02-02 19:05:51百科

妊娠(pregnancy)

从受精到分娩（参阅parturition），胎儿在女性体内发育的过程，又称为怀孕。在来自男性的精子与来自卵巢的卵在输卵管融合（参阅fertility、fertilization）的那一刻开始。受精卵（合子）向前往子宫的时候藉由细胞分裂而增大，陷入子宫壁并长成胚胎，接着成为胎儿。发育出胎盘与脐带作为母亲与胎儿之间的养分与废物交换之用。充满液体的羊膜包裹并保护胎儿缓和震动。妊娠早期较高浓度的雌激素与孕酮使月经停止，造成恶心，通常还会呕吐（孕妇晨吐），乳房变大并做好泌乳的准备。随着胎儿发育，子宫扩张迫使其他器官移位。妊娠正常会多9至11.5公斤。要提供胎儿营养需求，母亲必须摄取更多热量，更重要的是蛋白质、水分、钙和铁。在妊娠早期建议补充叶酸，避免神经管缺陷。吸烟、酒精以及许多合法非法药物会造成先天性疾病，在妊娠期间应该避免。超音波成像通常用於检查胎儿的组织发育与机能进展状况。预产期是从最後一次月经算起280天；90%的婴儿是在预产期的两个星期内出生。亦请参阅amniocentesis、preeclampsia and eclampsia、premature birth。

English version：

pregnancy

Process of human gestation that takes place in the female's body as a fetus develops, from fertilization to birth (see parturition). It begins when a viable sperm from the male and egg from the ovary merge in the fallopian tube (see fertility, fertilization). The fertilized egg (zygote) grows by cell division as it moves toward the uterus, where it implants in the lining and grows into an embryo and then a fetus. A placenta and umbilical cord develop for nutrient and waste exchange between the circulations of mother and fetus. A protective fluid-filled amniotic sac encloses and cushions the fetus. Early in pregnancy, higher estrogen and progesterone levels halt menstruation, cause nausea, often with vomiting (morning sickness), and enlarge the breasts and prepare them for lactation. As the fetus grows, so does the uterus, displacing other organs. Normal weight gain in pregnancy is 20-25 lbs (9-11.5 kg). The fetus's nutritional needs require the mother to take in more calories and especially protein, water, calcium, and iron. Folic-acid supplements are recommended during early pregnancy to prevent neural tube defects. Smoking, alcohol, and many legal and illegal drugs can cause congenital disorders and should be avoided during pregnancy. Ultrasound imaging is often used to monitor structural and functional progress of the growing fetus. The due date is estimated as 280 days from the time of last menstruation; 90% of babies are born within two weeks of the estimated date. See also amniocentesis, preeclampsia and eclampsia, premature birth.