Pregnancy brings about many changes in a woman’s body. These changes are both physical and hormonal, and begin right from conception. Let’s look at the key changes that occur during the 9 months of pregnancy.
Changes in the first trimester (0 to 13 weeks)
The first trimester marks the beginning of pregnancy. Here are the key changes:
Missed period – A missed period is often the first sign of pregnancy. Pregnancy hormones prevent the monthly shedding of the uterine lining (period).
Nausea and vomiting – Hormonal changes can cause nausea and morning sickness in early pregnancy. Many women feel sick and may throw up, especially in the morning.
Bigger breasts – Rising hormone levels cause the breast ducts and milk glands to grow and swell. The areola (area around the nipple) also darkens.
Food cravings and aversions – Changing hormones can trigger specific cravings and dislikes for certain foods and smells. These sensations are temporary.
Frequent urination – Hormones increase blood flow to the kidneys making you urinate more often. The growing uterus also presses on the bladder.
Fatigue and tiredness – Progesterone levels rise sharply in early pregnancy making you feel sleepy and tired. Rest as much as you can.
Heartburn – Hormonal changes relax the valve between the esophagus and stomach, causing heartburn. Eat small meals and avoid spicy and greasy foods.
Headaches – Changing estrogen and progesterone levels can trigger headaches and migraines in some women. Stay well hydrated and rest to ease headaches.
Changes in the second trimester (14 to 27 weeks)
In the second trimester, some of the unpleasant early symptoms subside. But the body continues to gear up to nourish and house the growing baby.
Visible baby bump – By mid-pregnancy the uterus grows above the pelvic bones becoming an obvious baby bump.
Stretch marks – Rapid growth causes the skin over the abdomen to stretch. Pink or purplish stretch marks may develop over the tummy, breasts, hips and buttocks.
Dark line on abdomen – Increased pigment causes a dark line called the linea nigra to run from pubic area to below the belly button.
Increased vaginal discharge – More estrogen stimulates mucus production from cervical glands leading to a clear or white vaginal discharge.
Leg cramps – Circulating hormones can cause leg muscle spasms and leg cramps, especially at night. Stretching before bed helps.
Itchy skin – The expanding belly stretches the skin which can feel very itchy. Lotions and oils help relieve stretch mark itchiness.
Dizziness – Pregnancy hormones relax blood vessels causing a drop in blood pressure. Changing positions slowly prevents dizziness.
Bleeding gums – Increased blood flow to the gums can cause swelling, tenderness and bleeding. Brush gently with a soft toothbrush and use pregnancy dental products.
Skin tags – Increased collagen production can cause harmless skin tags to develop on the neck and breasts. These usually disappear after delivery.
Varicose veins – Pressure from the uterus slows blood flow from legs to the heart causing varicose veins. Elevate legs whenever possible to ease swelling.
Congestion and nosebleeds – Higher estrogen and blood volume causes stuffiness and nosebleeds. Use saline drops and humidifiers for relief.
Backache – Extra weight, altered posture and loose joints strain the lower back muscles. Use support belts, heat packs and massage for back pain relief.
Changes in the third trimester (28 to 40 weeks)
The third trimester marks the home stretch of pregnancy. The mother’s body works hard to help the unborn baby develop fully.
Rapid weight gain – Weight gain speeds up to support the growth spurt of the fetus. On average, women gain 1 lb per week in the last trimester.
Shortness of breath – The expanding uterus presses up against the lungs and diaphragm making it harder to breathe deeply. Sit upright to maximize lung capacity.
Swelling of feet – Extra fluid gets retained causing swelling or edema of the feet and ankles. Elevate feet whenever possible to reduce swelling.
Insomnia – Discomfort from the growing uterus, heartburn, leg cramps and anxiety makes sleep difficult in late pregnancy. Nap during the day to offset lost nighttime sleep.
Clumsiness and forgetfulness – Physical awkwardness coupled with absent mindedness is common in late pregnancy. Don’t stress, this is temporary.
Braxton Hicks contractions – The uterus periodically contracts and tightens to prep for true labor. These warm ups are called false labor or Braxton Hicks contractions.
Stuffy nose – Swelling narrow nasal passages contributes to chronic stuffiness and congestion. Sleep with head elevated and use saline nasal sprays.
Increased vaginal discharge – Nearing labor, the cervix softens and dilates releasing mucus. Consult your doctor if the discharge is green or foul smelling.
Pelvic pain – Pressure on pelvic joints from the heavy uterus along with the baby’s movement causes pelvic and pubic bone pain. Try warm compresses.
Contractions – Towards the end the uterus contracts more often in preparation for labor. Time contractions if they get regular and intense.
Lightening – The baby’s head drops lower into the pelvis in a process called lightening. This relieves pressure on the lungs and stomach.
Nesting instinct – A burst of energy prompts some women to clean and organize just before labor. This nesting instinct is thought to prepare the home for the baby’s arrival.
Physical changes during pregnancy
Let’s take a closer look at some of the key physical changes that take place during the 9 months of pregnancy.
Breast changes
Under the influence of pregnancy hormones, the breasts enlarge and undergo important changes:
- Ducts and milk glands swell in preparation for breastfeeding
- Veins under the skin become more visible
- Areola diameter increases. Pigment causes darkening of the areola.
- Montgomery glands on the areola enlarge. These lubricate and protect the nipple.
- Breasts sometimes leak a watery pre-milk called colostrum
These changes prepare the breasts for the important job of producing milk to nourish the newborn. Breastsize increases by up to 2 cup sizes during pregnancy.
Skin changes
Pregnancy hormones stimulate the production of skin pigments, collagen fibers and skin oils. Common changes include:
- Darkening areola
- Dark line from pubis to belly button
- Facial pigmentation and chloasma (dark patches on face)
- New moles or darkening of existing moles
- Acne breakouts and pimples on face
- Dry and itchy skin
- Red palms and soles. Raised yellow bumps on palms.
- Stretch marks on abdomen, breasts, thighs and buttocks
- Itchy belly and growing bump
- Spider veins on legs
- Varicose veins
These skin changes gradually resolve after delivery once hormone levels return to normal. Stretch marks also fade and become less prominent over time.
Hair changes
Surging hormones have noticeable effects on hair growth and texture:
- Faster hair growth – many women report thicker, faster growing hair especially during the second trimester
- Hair loss – However, hair shedding increases after delivery
- Nails also grow faster
- Excess hair on face, arms, legs, back – a temporary effect of raised testosterone levels
- Changes in hair texture. Hair may appear shinier.
Post-pregnancy hair loss and growth resume their normal pace by 12 months. Excess hair also disappears within a year after childbirth.
Weight changes
Maternal weight gain supports the development of the fetus and prepares for breastfeeding:
- Average pregnancy weight gain is 25-35 lbs
- 2-5 lbs is baby’s weight
- 7-8 lbs is extra blood and body fluids
- 2 lbs breast tissue
- 2 lbs uterus enlargement
- 4 lbs amniotic fluid
- 7-8 lbs is maternal fat stores
- 4-6 lbs is retained water
This pregnancy weight is gradually lost over several months after delivery through breastfeeding and normal metabolism.
Body temperature changes
Basal body temperature is slightly higher in pregnancy. Body temperature spikes by about 1o F during ovulation and remains elevated after conception. This is the basis of BBT birth control and ovulation prediction kits.
Heightened senses
Nauseating smells, loud noises and strong tastes can overwhelm pregnant women due to hypersensitive smell and taste receptors under the influence of estrogen. These senses return to normal after childbirth.
Changing measurements
Here are some average measurements during pregnancy:
| Measurement | Early pregnancy | 24 weeks | 36 weeks |
|---|---|---|---|
| Fundal height (cm) | 16 cm | 24 cm | 32-34 cm |
| Uterus top to pubic bone (cm) | 3 cm | 12 cm | 24 cm |
| Total weight gain (lbs) | 1-4 lbs | 12-14 lbs | 25-28 lbs |
These changing dimensions reflect the growing uterus and baby inside. Measurements help assess fetal growth and uterine expansion during prenatal visits.
Changing hormones
Pregnancy leads to major hormonal adaptations:
- Human Chorionic Gonadotropin (hCG) – Secreted by placenta to maintain pregnancy. HCG is detected in the blood and urine by home pregnancy kits.
- Estrogen – Increases steadily leading to breast enlargement and milk duct growth. Also causes nausea, skin changes, uterine growth.
- Progesterone – Key hormone of pregnancy prevents preterm contractions and relaxes joints and tissues.
- Oxytocin – Released by the pituitary gland. Stimulates milk letdown during breastfeeding.
These hormones decline quickly after delivery of the placenta leading to postpartum changes and initiation of breastmilk production.
Maternal organs
Maternal organs undergo anatomical and functional changes to nurture the developing fetus.
Uterus – The uterine cavity expands from 50 gm to 1100 gm by late pregnancy. The walls thicken and become more vascular.
Placenta – The placenta forms by week 12 implanting deep into the uterine wall. It transfers oxygen and nutrients to the fetus and removes waste products.
Cervix – The cervix remains closed and protected by a mucus plug. It starts thinning and dilating several weeks before labor.
Ovaries – Ovulation stops for the duration of pregnancy. The corpus luteum secretes progesterone until the placenta takes over by 10 weeks.
Vagina – Increased blood flow causes engorgement of vaginal walls or the Chadwick’s sign. Higher mucus production also occurs.
These remarkable transformations enable a woman’s body to successfully nurture the developing fetus for 9 months.
Pregnancy effects on health
While pregnancy is a normal physiological state, it can influence a woman’s health in various ways:
Hematological changes
- Blood volume increases by 50% to meet demands of mother and fetus
- Red blood cells also multiply to transport more oxygen
- Risk of anemia as demand outstrips supply
This physiological anemia of pregnancy resolves with iron supplements and increased RBC production.
Cardiovascular changes
- Heart rate increases by 15-20 bpm
- Cardiac workload goes up
- Peripheral blood vessels dilate lowering BP
- Risk of supine hypotensive syndrome if lying flat
- Leg veins are prone to varicosities and clots
Careful monitoring and support stockings help prevent cardiovascular complications.
Respiratory changes
- Oxygen demand rises by 20-50%
- Lung capacity is restricted by the growing uterus
- Risk of nasal stuffiness and bleeding
Proper rest and good posture maximizes lung expansion needed for adequate gas exchange.
Metabolic changes
- Pregnancy is a hypermetabolic state
- Macronutrient needs are higher than normal
- Digestion slows down. Constipation common.
- Morning sickness causes poor oral intake
Good prenatal nutrition and supplements are vital to support the metabolic needs of pregnancy.
Skeletal changes
- Ligaments become lax. Pelvis tilts and widens.
- Postural adaptations to accommodate uterine growth
- Stress on lower back from weight gain
- Minerals like calcium are transferred to the fetus
Postnatal physiotherapy helps strengthen core muscles and regain abdominal tone.
Oral health
- Gums are sensitive. Pregnancy gingivitis common.
- Food cravings increase caries risk
- Gum bleeding due to inflammation
See your dentist and practice careful oral hygiene during pregnancy.
Thus pregnancy impacts almost every organ system due to structural and metabolic demands of the fetus. However, most changes reverse post-delivery once hormone levels stabilize.
How pregnancy changes urine
Pregnancy affects kidney function and urine in various ways:
- Increased glomerular filtration rate
- Increased urine production to remove fetal wastes
- Frequent daytime urination
- Nighttime trips to the bathroom
- Urine leaks with laughing or sneezing
- Higher risk of urinary tract infections
Changes in urine itself include:
- Dilute urine with low specific gravity
- Ketonuria due to fasting or inadequate calories
- Glycosuria or glucose spilling into urine
- Hematuria from bleeding gums or infections
- Proteinuria within normal limits during pregnancy
Thus pregnancy places extra demands on the urinary system. Staying well hydrated, voiding when needed and prompt UTI treatment ensures renal health.
Conclusion
Pregnancy transforms a woman’s body in wonderful ways to promote fetal growth and development. Hormones enrich these changes that enable her to carry the pregnancy, give birth to a healthy baby and nourish the newborn after delivery. While challenging at times, these biological adaptations help perpetuate the human race. If pregnancy occurs at a later age, extra medical care helps counter the risks associated with delayed childbearing.