Page 38 - (DK) Help Your Kids with Growing Up: A No-Nonsense Guide to Puberty and Adolescence

36 FEMALE PUBERT Y

The menstrual cycle SEE ALSO
‹
‹ 28–29 What is puberty?
30–31 Female hormones
The menstrual cycle is the process that enables a female’s body to ‹ 34–35 Female sex organs
make a baby. The cycle is counted from the first day of a period, Sanitary care 38–39 ›
to the day before the start of the next period.

How it works Oestrogen Progesterone
The female hormones, oestrogen and
progesterone, regulate the menstrual
cycle. As the levels of these hormones
rise and fall, the menstrual cycle Menstruation Lining builds up Lining maintained Lining breaks down
progresses. Its four stages take 28 days
on average, but can last from 21 up Day 1 Day 6 Day 14 Day 28
to 35 days. The length of each stage
may vary.
Uterus
Day 6–13
Egg The egg continues to mature in the ovary.
The lining of the uterus thickens to prepare
Ovary for a possible pregnancy.
Inner Fallopian
lining tube
Menstrual
Day 1–5 blood
The uterus sheds its inner
lining which leaves the body 6 7 8 9
through the vagina as blood. 5 10 Inner
Meanwhile, a new egg starts to 4 lining
mature in one of the ovaries. 11
3
12
2 Vagina
13
1
14
Day 14
28
15 The mature egg is released from
27 the ovary and it travels along the
Egg 16
Thickened fallopian tube towards the uterus.
lining 26
17 If the egg is fertilized by a sperm,
the thickened lining will cushion
25 18 it as it develops into a baby.
24 19
23
22 21 20 Egg
Day 15–28
If the egg is not fertilized by a sperm, the
thickened lining is no longer needed. The egg
breaks down and flows out of the uterus
during the next period.

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