Pregnancy is also known as the period of gestation or gravidity, during which a future offspring develops inside the female womb. The 9-month period of pregnancy is typically divided into three trimesters: the first one lasting from week 1 to week 12 including conception, the second trimester lasting from week 13 to week 28, while the third trimester spans from week 29 to approximately 40 weeks. During the first eight weeks following conception, the term ‘embryo’ is used, after which the term ‘fetus’ is used until delivery. Pregnancy can occur either through sexual intercourse or through assisted reproductive technology, such as in vitro fertilization. Childbirth may occur either naturally through the birth canal or via cesarean delivery.


Types of pregnancies:

Intrauterine pregnancy – normal pregnancy, when the fetus or fetuses implant inside the uterus, and the placenta is attached to the uterine muscle

Ectopic and tubal pregnancies – ectopic pregnancies occur when the fertilized egg implants in a place other than the fallopian tube or uterus, usually resulting in the body spontaneously aborting the fetus. Tubal pregnancies occur when the fertilized egg implants in the fallopian tube instead of the uterus

Intra-abdominal pregnancies – most intra-abdominal pregnancies occur after a previous C-section. The C-section scar may weaken and tear, allowing the fetus to slip into the abdominal cavity and the viability of the pregnancy will depend upon the gestational age of the fetus

Singlet pregnancy – singlet pregnancies occur when one egg meets one sperm and one fetus develops

Multiple pregnancy – multiples can occur as a result of multiple eggs being fertilized at the same time, when two sperm enter one egg or when one egg is fertilized by one sperm that divides into two zygotes. If more eggs are fertilized, the pregnancies will result in fraternal twins. If one egg was fertilized by two sperm, fraternal twins will result. If one egg splits into multiple zygotes, identical twins will occur

Molar pregnancy – complete molar pregnancies result in the placenta forming in the uterus without a fetus to support, while partial molar pregnancies occur when two sperm fertilize one egg, but two fetuses do not develop, the resulting placenta being abnormal with the fetus having too many chromosomes. This always results in a spontaneous abortion as the fetus cannot develop safely

Symptoms and signs

The first trimester:

Rapid changes for both the mother and developing fetus


Missing a period is usually the first signal of pregnancy, though women with irregular periods may encounter difficulties if relying solely on the absence of menstruation as a sign of a potential pregnancy

Extreme fatigue

Breast tenderness

Frequent need to urinate

Nausea and/or vomiting

Uterine cramping

Heart murmurs

Shortness of breath

Swollen ankles

Frequent emotional outbursts ranging from excitement to anxiety


The baby’s brain, spinal cord and other vital organs begin to develop

The baby’s heart begins to beat

Fingers and toes begin to take shape


The second trimester:

General improvement of physical and emotional changes


Larger breasts

Breast tenderness

Darkening of the areolas

Darkened veins due to increased blood flow

Growing abdomen

Skin changes (pigmentation) seen in the areolas, underarms, face, while the ‘linea alba’ becomes the ‘linea nigra’ (the vertical line linking the umbilicus with the pubis)

Progressive increase of an exaggerated lumbar curve (lordosis) resulting in back pain and increased need to urinate

Possible gait unsteadiness

Fetal movements are usually felt before 20 weeks’ gestation


Develops the ability to move and hear


The third trimester:

Physically and emotionally challenging

The changes in uterus growth range from an organ that weighs 70 g with a capacity of 1mL to an organ that weighs 1000 g and has the capacity of almost 20 L

The shape evolves from a pear-like outline to a more round, almost spherical outline by the early third trimester, by full term the uterus becoming ovoid

The uterus is completely palpable in the abdomen not just by pelvic examination at about 12-14 weeks’ pregnancy

Milk secretion is not uncommon even as early as the first trimester, but it usually does not occur until after delivery

Lactogenesis stages II and III occurs postpartum and produces more mature milk


Other physiological adaptations to pregnancy:

Potential sensation of dry eyes

Acne may either flare up or clear up during or right after pregnancy

Hair changes are fairly often, many women developing mild hirsutism (excessive male-pattern hair growth)

Occurrence of stretch marks

Total sleep time increases during the first trimester, it normalizes during the second and decreases during the third

  • The position of the baby inside the womb can indicate its sex

    Pregnant women should eat for two – during pregnancy an extra caloric intake of approximately 300 kcal/day is needed

    The sexual position during intercourse influences the baby’s gender – the baby’s gender can only be determined by the father’s genes that contain both the X and Y chromosomes, while women carry only the X chromosome. Still, this process cannot be actively controlled by either parents, let alone through the physical act of intercourse

    Older fathers increase the risk of having children with birth defects – the literature suggests a 0.3%-0.5% risk of autosomal dominant disease in offspring of fathers aged 40 years or older, while it is true that studies have also indicated a possible association between advanced paternal age and offspring with autism spectrum disorders and schizophrenia

    Seatbelts should not be worn during pregnancy – the seatbelt should be placed low, across the hip bones and under the pregnant abdomen, while pregnant women should try to maintain a 10 inches/25 cm distance from the airbag

    Traveling should be restricted altogether – possibilities vary according to the stage of the pregnancy and individual risks

    Sexual intercourse is dangerous during pregnancy – unless the woman experiences any bleeding, tissue rupture, and does not have a history of preterm labor or birth, more than one miscarriage or complications concerning the placenta, sexual activity need not be restricted

    Exercising should be avoided altogether – mild forms of physical activity are recommended (though contact sports, weightlifting, aerobics or any other demanding forms of exercise should be avoided for fear of injury)

    Women should restrict work while pregnant – unless pregnancy risks and complications constitute an impediment to the health of both the mother and the baby, work need not be limited

    Fish should be highly avoided, especially raw fish – due to potential exposure to methylmercury (industrial pollution of waters) pregnant women should eat a minimum amount of fish, such as: shrimp, canned light tuna, salmon, Pollock and catfish up to a maximum of 2-3 servings per week. Though shark, swordfish, king mackerel, or tilefish should be avoided altogether due to high levels of methylmercury

    Caffeine should be eliminated altogether – clinicians recommend limiting daily intake of caffeine to a maximum of 200 mg/day, no more than about two cups

    Pregnant women should sleep on their left side – whichever side feels comfortable is safe

    A bigger baby is a healthier baby

    Drinking dark beer helps milk production

    Pregnant women should avoid dying their hair or wearing nail polish – although there is a theoretical risk of absorbing certain chemicals through skin, there has been no evidence of these posing a real danger to pregnancy, especially since only exposure to large quantities of chemicals would constitute a real risk


Maternal mortality fell by 44% since 1990

Every year, an estimated 15 million babies are born preterm, which is defined as babies born alive before 37 weeks of pregnancy are completed, this being the leading cause of death globally in children under the age of five

About 16 million women 15–19 years old give birth each year, about 11% of all births worldwide

More than 50% of pregnant females complain of back pain during pregnancy, while roughly 4-6 per 1000 women will develop scoliosis

More than 90% of women exhibit skin darkening during pregnancy

During pregnancy, women expand their blood volume by approximately 30-50%

The heart rate may also increase by 10-20 beats per minute

Mean blood pressure level decreases 6-10 mm Hg

About two thirds of white women and only 10% of black women experience symptoms of spider angioma (abnormal collection of blood vessels near the surface of the skin) and palmar erythema (reddening of the hands)

Did you know?

The fertilized conceptus enters the uterus as a 2- to 8-cell embryo and freely floats in the endometrial cavity (uterus) about 90-150 hours, roughly 4-7 days after conception, after which it implants onto the uterinewall and determines a series of physiological changes meant to establish the maternal-placental exchange

The most accurate of pregnancy tests measure the level of gonadotropin (human chorionic gonadotropin – hCG) a hormone that is produced beginning on the day of the embryo’s implantation and it can be effectively detected in both blood and urine after approximately 8-9 days after conception

Breast milk usually comes in approximately three to six days after delivery

The uterus returns to prepregnancy size after approximately 6 weeks through a process called involution

During involution, the uterus has contractions that women may be able to feel, especially during breastfeeding

Vaginal discharge that decreases in redness and flow, in addition to menstrual-like cramping are fairly common after delivery

Women usually can resume sexual intercourse when they feel ready, typically 4-6 weeks after delivery and when bleeding has substantially decreased

Liver should also be eaten in moderation during pregnancy due to containing high levels of vitamin A

Products such as unpasteurized milk, including soft cheeses like brie, feta, and blue cheese, unpasteurized juice, raw or partially cooked meat and eggs, in addition to raw sprouts should be avoided altogether during pregnancy in order to prevent foodborne illnesses


In 2009 the Institute of Medicine released guidelines for weight gain during singleton pregnancy:

Underweight women (BMI < 18.5) should gain 28-40 pounds (12-18 kg)

Normal-weight women (BMI, 18.5-24.9) should gain 25-35 pounds (11-15 kg)

Overweight women (BMI, 25-29.9) should gain 15-25 pounds (6-11 kg)

Obese women (BMI, 30 or higher) should gain 11-20 pounds (4.9-9 kg)


17 November 2014 was declared World Prematurity Day