Fundal height, or McDonald's rule, is a measure of the size of the

uterus The uterus (from Latin ''uterus'', plural ''uteri'') or womb () is the organ in the reproductive system of most female mammals, including humans that accommodates the embryonic and fetal development of one or more embryos until birth. The ...

used to assess

fetal growth Prenatal development () includes the development of the embryo and of the fetus during a viviparous animal's gestation. Prenatal development starts with fertilization, in the germinal stage of embryonic development, and continues in fetal devel ...

and development during

pregnancy Pregnancy is the time during which one or more offspring develops ( gestates) inside a woman's uterus (womb). A multiple pregnancy involves more than one offspring, such as with twins. Pregnancy usually occurs by sexual intercourse, but ...

. It is measured from the top of the mother's uterus to the top of the mother's pubic symphysis. Fundal height, when expressed in centimeters, roughly corresponds to gestational age in weeks between 16 and 36 weeks for a vertex fetus. When a tape measure is unavailable, finger widths are used to estimate centimeter (week) distances from a corresponding anatomical landmark. However, landmark distances from the pubic symphysis are highly variable depending on body type. In clinical practice, recording the actual fundal height measurement from the palpable top of the uterus to the superior edge of the pubic symphysis is standard practice beginning around 20 weeks gestation. Most caregivers will record their patient's fundal height on every prenatal visit. Measuring the fundal height can be an indicator of proper fetal growth and amniotic fluid development. Knowledge of gestational age may impact how the height is measured.

Fundal height landmarks

Shorter measure

A shorter measure can happen for one of the following reasons: *Fetus descent into the pelvis, seen normally two to four weeks before delivery *Error in estimated date of pregnancy based on first day of last menstrual period *Fetus is healthy but physically small *

Oligohydramnios Oligohydramnios is a medical condition in pregnancy characterized by a deficiency of amniotic fluid, the fluid that surrounds the fetus in the abdomen, in the amniotic sac. It is typically diagnosed by ultrasound when the amniotic fluid index ( ...

*Non longitudinal lie * Small for gestational age or

Intrauterine Growth Restriction Intrauterine growth restriction (IUGR), or fetal growth restriction, refers to poor growth of a fetus while in the womb during pregnancy. IUGR is defined by clinical features of malnutrition and evidence of reduced growth regardless of an infant's ...

Longer measure

On the other side, a longer measure can be caused by: *

Twins Twins are two offspring produced by the same pregnancy.MedicineNet > Definition of TwinLast Editorial Review: 19 June 2000 Twins can be either ''monozygotic'' ('identical'), meaning that they develop from one zygote, which splits and forms two em ...

, or other types of

multiple births A multiple birth is the culmination of one multiple pregnancy, wherein the mother gives birth to two or more babies. A term most applicable to vertebrate species, multiple births occur in most kinds of mammals, with varying frequencies. Such bir ...

*Error in estimated date of conception *Fetus is healthy but physically large *

Gestational diabetes Gestational diabetes is a condition in which a woman without diabetes develops high blood sugar levels during pregnancy. Gestational diabetes generally results in few symptoms; however, it increases the risk of pre-eclampsia, depression, and ...

causing a larger baby *

Polyhydramnios Polyhydramnios is a medical condition describing an excess of amniotic fluid in the amniotic sac. It is seen in about 1% of pregnancies. It is typically diagnosed when the amniotic fluid index (AFI) is greater than 24 cm. There are two clini ...

* Large for gestational age *

Hydatidiform Mole A molar pregnancy also known as a hydatidiform mole, is an abnormal form of pregnancy in which a non-viable fertilized egg implants in the uterus. A molar pregnancy is a type of gestational trophoblastic disease that used to be known as a ''hy ...

Breech birth A breech birth is when a baby is born bottom first instead of head first, as is normal. Around 3–5% of pregnant women at term (37–40 weeks pregnant) have a breech baby. Due to their higher than average rate of possible complications for the ...

As a

approaches its end, the fundal height will become less accurate. Symphysiofundal height is more accurate at 14–32 weeks.

References

{{DEFAULTSORT:Fundal height Obstetrics Midwifery