Bma Illustrated Medical Dictionary

egg implants into an abnormal site,

such as a fallopian tube, resulting in an

ectopic pregnancy.

A normal pregnancy lasts around 40

weeks from the first day of the woman’s

last menstrual period. It is divided into

3 stages (trimesters) of 3 months each.

For the first 8 weeks of pregnancy, the

developing baby is called an embryo;

thereafter it is called a fetus.

In the 1st trimester the breasts start to

swell and may become tender. Morning

sicknessis common. The baby’s major

organs have developed by the end of

this stage. During the 2nd trimester, the

mother’s nipples enlarge and darken

and weight rises rapidly. The baby is

usually felt moving by 22 weeks. During

the 3rd trimester, stretch marks and

colostrummay appear, and Braxton Hick’s

contractionsmay be felt. The baby’s

head engages at about 36 weeks.

Common, minor health problems dur-

ing pregnancy include constipation,

haemorrhoids, heartburn, pica, swollen

ankles, and varicose veins. Other com-

mon disorders include urinarytract

infections, stress incontinence (see in-

continence, urinary), andcandidiasis.

Complications of pregnancy and disor-

ders that affect it include antepartum

haemorrhage; diabetic pregnancy; mis-

carriage; polyhydramnios; pre-eclampsia;

prematurity; and Rhesus incompatibility.

(See also childbirth; fetal heart monitor-

ing; pregnancy,multiple.)

pregnancy, drugs inCertain drugs

taken during pregnancymay pass to the

fetus through the placentaor interfere

with fetal development. This may lead

to birth defects. Although relatively few

drugs have been proved to cause harm

to a developing baby, no drug should be

considered completely safe, especially

during early pregnancy. For this reason,

pregnant women should seek advice

from their doctor or pharmacist before

taking any drug, including over-the-

counter preparations,

Problems may also be caused in a

developing baby if a pregnant woman

drinks alcohol, smokes (see tobacco-

smoking), or takes drugs of abuse. The

babies of women who useheroin during

pregnancy tend to have a low birthweight

and a higher death rate than normal

during the first few weeks of life. Babies

of women who abuse drugs intravenously

are at high risk of HIVinfection.

pregnancy, falseAn uncommon psy-

chological disorder, medically known as

pseudocyesis, in which a woman has

physical signs of pregnancy, including

morning sickness, amenorrhoea (ab-

sence of periods), enlarged breasts, and

abdominal swelling, but is not pregnant.

The woman is convinced that she is

pregnant. Treatment for false pregnancy

PREGNANCY

Fetus

Enlarging

uterus

Slightly
swollen
breasts

Intestine

Uterus

Fetus

AT 12 WEEKS AT 24 WEEKS AT 36 WEEKS

Fully

formed

fetus

Head of

fetus over

pelvis

Mucus plug

protecting fetus

from infection

Enlarged

milk

glands

Swollen

abdomen

Slightly
thickened
waistline

Intestine

compressed

by uterus

Bladder

PREGNANCY, DRUGS IN PREGNANCY, FALSE

P