Hormonal changes may seem like the bane of every expectant mum’s existence, but they are actually essential to a safe and healthy pregnancy.
So, before you go blaming and cursing all your strange symptoms on those darn hormones, find out how these chemical messengers boost your blossoming body.
1. hCG, or human Chorionic Gonadotropin
The first sign of a hormonal change you’ll notice will probably be in the form of the positive sign you see on your pregnancy test stick. Pregnancy test sticks confirm a pregnancy by picking up the presence of the hormone hCG in an expectant mum’s urine. hCG levels in a woman’s blood generally double every two to three days in early pregnancy.
hCG is created by your placenta cells, which then stimulate the production of two other important hormones ― oestrogen and progesterone. Peaking at around 10 to 12 weeks, hCG levels then start to decline in the second trimester, when the placenta takes over the production of oestrogen and progesterone.
While typical hCG levels can vary, lower or stagnant levels tend to indicate a tendency to miscarry, or may point to an ectopic pregnancy. Still, don’t get too worked up over your hCG numbers ― some perfectly healthy and successful pregnancies have quite low levels of hCG.
hCG levels may be blamed for certain early pregnancy symptoms, like tender breasts and a sensitive bladder (since it’s responsible for increasing the blood supply to your pelvic area). Some believe that it’s linked to the nausea and vomiting mums-to-be experience in the first trimester.
Pregnancy test sticks confirm a pregnancy by picking up the presence of the hormone hCG in an expectant mum’s urine.
Oestrogen (along with progesterone) plays a crucial role in your baby’s development during pregnancy. Both these hormones are produced by the corpus luteum, a cyst on the ovary, until around the tenth week, when the placenta takes over.
Oestrogen helps your uterus to grow, increases blood flow around your body, and maintains your uterine lining that keeps bubba safe. It also helps your baby’s little organs to develop, and regulates your baby’s bone density. This hormone is also responsible for your middle-of-the-night cravings, as well as morning sickness.
On the downside, oestrogen can have negative effects on the mum-to-be’s skin ― your skin colour may change, and it can cause spider veins (clusters of tiny blood vessels close to the surface of the skin) in the face and legs. However, if you’re lucky, you may get what people commonly call the “pregnancy glow”.
Along with oestrogen, progesterone is a vital hormone that supports your pregnancy. Both work together to suppress further ovulation during pregnancy.
Progesterone performs a number of key functions during pregnancy ― besides helping preventing your immune system from rejecting the embryo (it’s technically a foreign body), it maintains the lining of your uterus.
Progesterone helps your baby to develop, and also softens your ligaments and cartilage to prepare you for labour. It also boosts the growth of breast tissue and milk-producing glands to prepare you for breastfeeding. If your progesterone levels are too low, your gynae may encourage you to take progesterone supplements to support your pregnancy.
The increase in the expectant mum’s progesterone levels may be responsible for her breast tenderness, mood swings, as well as the fatigue many of these women feel.
The “love hormone”, as it is often known, starts to build up in early pregnancy, and continues to increase through delivery and the birth of your baby. It’s useful as it promotes intimacy, so you may find yourself getting closer to your husband or even the rest of your family, especially in the last trimester. Oxytocin also promotes caution, which is definitely useful when you’re growing a baby, as you’ll make sure that you and your little one will not be harmed.
As you go into labour, oxytocin stimulates your uterus to contract. The contractions trigger even more oxytocin to be released, so that the contractions will increase in frequency and intensity. Manufactured oxytocin is sometimes used to induce labour, or further increase the intensity of the contractions.
Once bubba is safe in your arms, you’ll be encouraged to make skin-to-skin contact, which will release a flood of oxytocin. This promotes that feeling of bonding and connectedness to your baby, making you want to care for him.
When you breastfeed, oxytocin promotes the letdown effect, where the milk glands contract, squeezing milk into the ducts.
As you go into labour, oxytocin stimulates your uterus to contract. The contractions trigger even more oxytocin to be released.
You know that seemingly impossible task of squeezing a full-term baby through your pelvis? This is made possible thanks to the hormone relaxin, the chemical that helps you prepare for labour by relaxing your bones, muscles and ligaments, and softening your cervix. Relaxin also allows your abdominal muscles to stretch for your baby, as well as relaxes your arteries, which need to accommodate the surge in blood volume, while maintaining your blood pressure.
However, this is also the hormone that can cause pain such as backache, as it also relaxes your spinal ligaments. It may also produce pelvic girdle pain, causing you to feel wobbly and unstable, so watch your posture during this time.
6. Placental growth factor and HPL
Placental growth factor is a hormone that promotes the growth of your blood vessels during pregnancy. Low levels of placental growth factor can cause high blood pressure and pre-eclampsia in pregnancy.
HPL, or Human Placental Lactogen, is a protein hormone that’s formed by the placenta. It usually starts to form around the sixth week, through to the end of the pregnancy. HPL helps to decrease the expectant’s mum use of glucose, so that baby can use it for growth and development.
Produced in the pituitary gland, prolactin levels increase 10 to 20 times during pregnancy. This hormone stimulates the production of breastmilk during and after pregnancy. As it also inhibits ovulation during the first few months of breastfeeding, the nursing mum usually doesn’t get her period during this time. Over time, prolactin levels fall and the mum may start to ovulate again.
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