See also ABORTION; CHILDBIRTH; CONCEPTION; FETAL
ALCOHOL SYNDROME; PRENATAL CARE; STILLBIRTH.
fibroadenoma A benign (noncancerous) tumor
of the BREASTcomposed of a mix of fibrous and
glandular tissues. Fibroadenoma is the most com-
mon benign breast tumor and most often develops
in women under age 30. Researchers do not know
what causes fibroadenoma. Many women who
develop fibroadenomas have higher than normal
levels of ESTROGENS in their BLOOD circulation,
though researchers do not know the extent to
which this contributes. Fibroadenomas tend to
grow during PREGNANCY and shrink after
MENOPAUSE, supporting at least some level of hor-
monal involvement.
Most often the woman detects fibroadenoma as
a lump she feels in her breast during BREAST SELF-
EXAMINATION(BSE) or the doctor finds the fibroade-
noma during the breast exam portion of the284 The Reproductive System
HIGHLIGHTS OF FETAL GROWTHFetal Age Fetal Size Key Developments
(Gestational Weeks)
14 3 inches in length face clearly formed
LIVERproduces erythrocytes
18 6 inches in length lanugo (fine HAIR) on head
movement may be detectable
sucking
gastrointestinal tract produces meconium
24 11 inches in length viability possible with intensive medical care
one pound in weight movement apparent
eyebrows and eyelashes
fingerprints and footprints
heartbeat detectable with stethoscope
gender detectable with ULTRASOUND
startle REFLEX
28 15 inches in length viability possible
two to three pounds in weight eyelids open and close
increasing level of BRAINand NERVOUS SYSTEMfunctions
alveoli in LUNGS
32 17 inches in length viability probable
four pounds in weight body fat
BREATHINGmovements in lungs
36 19 inches in length viability likely
five to six pounds in weight fingernails completely cover fingertips
head hair replaces lanugo on head
40 20 to 21 inches in length viable, full term
seven to eight pounds in weight body lanugo disappears
lungs mature