Pregnancy


Pregnancy is the time during which one or more offspring gestates inside a woman's uterus. A multiple pregnancy involves more than one offspring, such as with twins.
Conception usually occurs following vaginal intercourse, but can also occur through assisted reproductive technology procedures. A pregnancy may end in a live birth, a miscarriage, an induced abortion, or a stillbirth. Childbirth typically occurs around 40 weeks from the start of the last menstrual period, a span known as the gestational age; this is just over nine months. Counting by fertilization age, the length is about 38 weeks. Implantation occurs on average 8-9 days after fertilization. An embryo is the term for the developing offspring during the first seven weeks following implantation, after which the term fetus is used until the birth of a baby.
Signs and symptoms of early pregnancy may include missed periods, tender breasts, morning sickness, hunger, implantation bleeding, and frequent urination. Pregnancy may be confirmed with a pregnancy test. Methods of "birth control"—or, more accurately, contraception—are used to avoid pregnancy.
Pregnancy is divided into three trimesters of approximately three months each. The first trimester includes conception, which is when the sperm fertilizes the egg. The fertilized egg then travels down the fallopian tube and attaches to the inside of the uterus, where it begins to form the embryo and placenta. During the first trimester, the possibility of miscarriage is at its highest. Around the middle of the second trimester, movement of the fetus may be felt. At 28 weeks, more than 90% of babies can survive outside of the uterus if provided with high-quality medical care, though babies born at this time will likely experience serious health complications such as heart and respiratory problems and long-term intellectual and developmental disabilities.
Prenatal care improves pregnancy outcomes. Nutrition during pregnancy is important to ensure healthy growth of the fetus. Prenatal care also include avoiding recreational drugs, taking regular exercise, having blood tests, and regular physical examinations. Complications of pregnancy may include disorders of high blood pressure, gestational diabetes, iron-deficiency anemia, and severe nausea and vomiting. In the ideal childbirth, labour begins on its own "at term". Babies born before 37 weeks are "preterm" and at higher risk of health problems such as cerebral palsy. Babies born between weeks 37 and 39 are considered "early term" while those born between weeks 39 and 41 are considered "full term". Babies born between weeks 41 and 42 weeks are considered "late-term" while after 42 weeks they are considered "post-term". Delivery before 39 weeks by labour induction or caesarean section is not recommended unless required for other medical reasons.

Terminology

Associated terms for pregnancy are gravid and parous. Gravidus and gravid come from the Latin word meaning "heavy" and a pregnant female is sometimes referred to as a gravida. Gravidity refers to the number of times that a female has been pregnant. Similarly, the term parity is used for the number of times that a female carries a pregnancy to a viable stage. Twins and other multiple births are counted as one pregnancy and birth.
A woman who has never been pregnant is referred to as a nulligravida. A woman who is pregnant for the first time is referred to as a primigravida, and a woman in subsequent pregnancies as a multigravida or as multiparous. Therefore, during a second pregnancy a woman would be described as gravida 2, para 1 and upon live delivery as gravida 2, para 2. In-progress pregnancies, abortions, miscarriages and/or stillbirths account for parity values being less than the gravida number. Women who have never carried a pregnancy more than 20 weeks are referred to as nulliparous.
A pregnancy is considered term at 37 weeks of gestation. It is preterm if less than 37 weeks and post-term at or beyond 42 weeks of gestation. The American College of Obstetricians and Gynecologists have recommended further division with early term 37 weeks up to 39 weeks, full term 39 weeks up to 41 weeks, and late term 41 weeks up to 42 weeks. The terms preterm and post-term have largely replaced earlier terms of premature and postmature. Preterm and postterm are defined above, whereas premature and postmature have historical meaning and relate more to the infant's size and state of development rather than to the stage of pregnancy.

Demographics

About 213 million pregnancies occurred in 2012, of which, 190 million were in the developing world and 23 million were in the developed world. The number of pregnancies in women aged between 15 and 44 is 133 per 1,000 women. Pregnancy rates are 140 per 1000 women of childbearing age in the developing world and 94 per 1000 in the developed world. The rate of pregnancy, as well as the ages at which it occurs, differ by country and region. It is influenced by a number of factors, such as cultural, social and religious norms; access to contraception; and rates of education. The total fertility rate in 2024 was estimated to be highest in Niger and lowest in South Korea.
About 10% to 15% of recognized pregnancies end in miscarriage. In 2016, complications of pregnancy resulted in 230,600 maternal deaths, down from 377,000 deaths in 1990. Common causes include bleeding, infections, hypertensive diseases of pregnancy, obstructed labour, miscarriage, abortion, or ectopic pregnancy. Globally, 44% of pregnancies are unplanned. Over half of unplanned pregnancies are aborted. In countries where abortion is prohibited, or only carried out in circumstances where the mother's life is at risk, 48% of unplanned pregnancies are aborted illegally. Compared to the rate in countries where abortion is legal, at 69%. Among unintended pregnancies in the United States, 60% of the women used birth control to some extent during the month pregnancy began.
In the United States, a woman's educational attainment and her marital status are historically correlated with childbearing: the percentage of women unmarried at the time of first birth drops with increasing educational level. Three studies conducted between 2015 and 2018 indicate a large fraction of women without a high school diploma or local equivalent in the US are unmarried at the time of their first birth. By contrast, the same studies indicated fewer women with a bachelor's degree or higher have their first child while unmarried. However, this phenomenon also has a strong generational component: a 1996 study found 48.2% of US women without a bachelor's degree had their first child whilst unmarried, and only 4% of women with a bachelor's degree had their first child whilst unmarried. These studies indicate a rising trend for US women of all educational levels to be unmarried at the time of their first birth.

Teenage pregnancy

is also known as adolescent pregnancy. The WHO defines adolescence as the period between the ages of 10 and 19 years. Adolescents face higher health risks than women who give birth at age 20 to 24 and their infants are at a higher risk for preterm birth, low birth weight, and other severe neonatal conditions. Their children continue to face greater challenges, both behavioral and physical, throughout their lives. Teenage pregnancies are also related to social issues, including social stigma, lower educational levels, and poverty. Female adolescents are often in abusive relationships at the time of their conceiving.

Diagnosis

is typically the cause of pregnancy, although myths regarding other sexual acts persist, particularly in populations that received poor sex education such as abstinence-only. Pregnancy can also be the result of assisted reproductive technology.
The beginning of pregnancy may be detected based on the woman's symptoms or by using pregnancy tests. Denial of pregnancy by the woman is a common condition with serious health implications. About 1 in 475 denials will last until around the 20th week of pregnancy. Denial persisting until delivery occurs in about 1 in 2,500 cases. Conversely, some non-pregnant women have a strong belief that they are pregnant along with some physical changes. This condition is known as a false pregnancy.

Symptoms and signs

Most pregnant women experience a number of symptoms which can signify pregnancy such as breast tenderness or morning sickness. A number of early medical signs are associated with pregnancy. Physical signs of pregnancy include:
Other common symptoms include constipation, back pain, pelvic girdle pain, headaches, and food cravings or food aversions. Pregnant women may also experience urinary tract infections, increased urinary frequency, worsened sleep quality, increased dream recall, and nightmares. In later pregnancy, hemorrhoids are more common. Each person's pregnancy can be different and many women do not experience all of the common signs and symptoms. The usual signs and symptoms of pregnancy do not significantly interfere with activities of daily living or pose a health-threat to the mother or fetus. Complications during pregnancy can cause other more severe symptoms, such as those associated with anemia.