Pregnancy Second Trimester: Problems, Lab Test, and Growth of the Baby

Developments during Second Trimester-

  • The onset of second trimester means that the anxieties, fears along with nausea and vomiting of first trimester will now recede.
  • By this time the body is quite a bit adapted to the changing hormones and hence overall it’s a pleasant period. Also by now grossly all the organs of baby have been formed, so now their maturation and development continues along with formation of fine structures like cochlea.
  • Hence infections and all are not as dangerous as in first trimester.
  • Placenta is formed and the baby is securely positioned, hence limited travelling is safe too.
  • Weight gain occurs since the appetite improves. Mood swings decrease and a feeling of general well being ensues.
  • Bladder irritability decreases and you make less trips to washroom at night!
  • Sex drive comes back and there is a renewed interest in sex since blood flow to pelvic organs increases too. It is safe to have sex in second trimester until and unless medically contraindicated!
  • The most happening part about this trimester is that one starts perceiving movements of baby in this period. At around 16 weeks first movements are felt like butterflies in stomach! In first pregnancy it takes a bit of time to make out the movements, hence most primates are able to perceive by 18 to 20 weeks.
  • Mother’s perceive 88% of fetal movements detected by Doppler imaging.

Minor problems during Second Trimester

  • Fullness Of breasts
  • Urine Incontinence, hence starting practicing keigel’s exercises at this very time is a good idea.
  • Constipation and Hemorrhoids (Due to pressure of enlarging uterus), hence a high fiber diet and lots of water are a must.
  • Gas and bloating
  • Varicose veins
  • Heartburn / Acidity : Due to compression of stomach by enlarging uterus. By 25weeks your uterus is around the size of a soccer ball (football).
  • Sometimes nasal bleed – becomes of increased blood volume in th body
  • Pigmentation on forehead, cheeks, nose and around to eyes (Due to hormonal imbalance)
  • Increased thirst: Pregnancy is a state of hypervolemia; due to changing levels of hormones estrogen, progesterone, aldosterone along with changes in osmoregulation there is resetting of osmotic thresholds for thirst. Increase in water intake due to lowered osmotic threshold for thirst causes polyuria ( increased urination) in early pregnancy.
  • Rarely bleeding gums, sweating or vaginal discharge again due to increased blood volume and hormonal changes
  • Increased vaginal discharge: it is due to hormone estrogen and is harmless.
  • Acne: perhaps the most unwanted sign of pregnancy, again the cause is raging hormones (specifically progesterone) of pregnancy! One can do anything about them, just let the phase pass. The good part is that these fade after pregnancy.
  • Itchy skin: it is due to stretching of skin due to increasing body size. Apply oils and keep the skin well hydrated, that’s all one needs to do.
  • Backache: in lower back, more pronounced by end of second trimester, due to laxity of pelvic ligaments by hormone relaxing in process of preparing body for childbirth.
  • Swollen feet: usually physiological(normal), appear by 18 to 20 weeks, more by evening and relieved by overnight rest, massage, wearing comfortable footwear and avoiding periods of prolonged standing. However one should exercise caution and always get a swollen feet checked by the doctor, since it could very well be the first sign of PIH (pregnancy induced hypertension)
  • Pre-Ecclampsia or PIH makes its appearance usually around 20 weeks. Even those with normal pre pregnancy Blood Pressure can also be affected. Symptoms include headache, vision changes, vomiting, shortness of breath, and swelling of hands and feet. This is a dangerous condition for both the mother and the baby. Early detection and management is the key. Hence it is imperative to get the BP checked every month.

Care during Pregnancy Second Trimester-

  • Overall a good balanced diet, constituting of high fiber and eating in small portions at short intervals along with the nutritional supplements (Iron, Multivitamin and calcium) prescribed by your doctor helps tiding over problems like constipation & fatigue.
  • One must make sure to eat hygienic well cooked food items, especially meat. Food poisoning must be avoided at all costs!
  • One should avoid gaining excessive weight, since in this period there is a renewed appetite due to feeling of general well being (the tornado of hormones of first trimester has settled and the problems of increasing size of gravid uterus have not yet started!). For an average person, the weight gain in this period is about 1kg per month.
  • Go for a high protein diet; avoid excess deep fried items, junk food and those high calorie ghee based sweets like laddoo, which are most commonly fed to pregnant women in our country. Better go for nuts, eggs, whole grains, jaggery etc.
  • It is a good idea to indulge in pregnancy safe exercises as advised by your antenatal care provider. At least walking should be done regularly to get a fit pregnancy.
  • Fetal movement count is the marker of fetal well being. You will be advised to keep a daily check of fetal counts once you start perceiving fetal movements well. The counts are begun from 28th week onwards.
  • There are two methods for it, any of which might be suggested to you by your doctor :


  • Cardif ‘count 10’ formula: woman counts fetal movement starting at 9am. The counting comes to an end as soon as 10 movements are perceived. She is instructed to report to the doctor if : # less than 12 movements occur during 12 hours on 2 successive days # no movement is perceived even after 12 hours in a single day.
  • Daily Fetal Movement Count (DFMC): Three counts each of one hour duration (morning, noon and evening) are recommended. The total counts multiplied by four gives daily (12 hour) fetal movement. If there is diminution of the number of ‘kicks’ to less than 10 in 12 hours (or less than 3 in each hour), it indicates fetal compromise and should be reported immediately.


Lab  tests  during second trimester

  • Triple Test: done between 15 to 18 weeks. Comprises of MSAFP, HCG and UE3 (maternal serum alfa protein, beta HCG hormone and unconjugated estradiol level). It gives a risk ratio and for confirmation amniocentesis has to be done.
  • Acetyl Chorine Esterase (ACHE) : level raised in amniotic fluid in cases of open neural tube defect in fetus.
  • Inhibin A: level raised in blood in woman carrying a fetus with Down syndrome.
  • In special situations, as assessed by your physician, certain invasive specialized tests are ordered like, amniocentesis, cordocentesis and chorionic villous sampling.
  • Routine tests, like HB, blood counts, blood sugar, thyroid function tests, urine routine and culture etc. if needed will be advised by your doctor.

Growth of the baby-

  • By the start of second trimester (week), the external structure of the baby is completely formed. It now looks like a mini human being.
  • Size ( on USG): At 14 weeks : 3 ¼ inches to 4 inches

                           At 20 weeks: 5 2/3  inches to 6 ½  inches

                           At 28 weeks: 14 inches

  • Urinary system: By the end of first trimester, the nephrons become active and start secreting urine. Kidneys are not essential to survival of fetus in utero, but play a role in regulating the volume of liquor.
  • At around the 16th week, lanugo,( thin, colorless hairs appear all over the body of fetus). These are important to provide insulation to the baby while floating in amniotic fluid. They almost completely disappear by term, and the remaining ones disappear a few days after birth!
  • Vernix caseosa: The waxy or cheesy substance covering the body of newborn at birth is actually secretions of sebaceous glands mixed with exfoliated epidermal cells! These sebaceous glands are formed at around 16 weeks. Various uses have been postulated of Vernix caseosa (also known as vernix, is the waxy or cheese-like white substance found coating the skin of newborn human babies.) like: providing waterproofing, providing insulation and preventing heat loss from body inside the uterus as well as few hours after birth.
  • Breathing movements can be identified as early as 11 weeks, but are irregular until 20 weeks.
  • The swallowing movements can be identified as early as 12 weeks and meconium(the dark green substance forming the first faeces of a newborn infant.) appears at around 20 weeks. Intestinal movements called peristalsis also begin, and that’s why the meconium is evenly spread till rectum at term!
  • The cochlea ( internal ear) forms by 16 weeks, and so yes it’s true that your baby can hear you now!( Remember the story of Abhimanyu from Mahabharata! Now you have a perfectly logical and believable scientific explanation for it!)
  • First facial expressions begin to appear as early as 17th week.
  • At 20 weeks a complete anomaly scan is done, since now the fetus is grown up enough to make a correct estimate of all organs by visualizing them, also the movements of baby can be assessed. If lucky you may catch your little one yawning at the scan! What a heartwarming sight!
  • An assessment is made based on the results of triple marker test and scan; and if needed you would be referred for a Level 3 scan and/or a fetal ECHO! These scans though elaborate, there are chances that they will miss an anomaly specially one which is not grossly visible.
  • The youngest baby to survive in India, baby Nirvaan, as mentioned in Hindustan Times 24 September 2017 & TOI 23 September 2017, was born at 22weeks
  • By 21 weeks fetal circulatory system is completely developed.
  • The eyes are still closed, but they develop sensitivity to light. The ability to open and close eyelids appears at around 27th week.
  • By 24weeks baby is about the size of a papaya! It now lands in a phase of growth spurt! Its systems are almost completely formed now, the fine maturation continues. 24 weeks is thus considered a time of viability. If for some reason you deliver now, there is a descent chance of survival of the baby if kept in a tertiary neonatal care setup.
  • At around 25 weeks, surfactant, the chemical mandatory to functioning of respiratory system makes its appearance. At this stage the baby also starts responding to mother’s voice. Actually mother’s voice, since it reverberates through the body, is clearest of all to the baby. The brain waves now emitted resemble quite a lot to the newborn brain waves. The baby also forms a sleep wake cycle of its own!
  • Experts studying the brain waves, now tell, that babies dream in uterus too!
  • Fat content in the body of the baby gradually increases in second trimester. From around 27th week the rate of fat deposition markedly increases.
  • 27th week, the last week of second trimester, is the time when lungs, the last organ in body to mature, are developed sufficiently to make the baby breath in external environment with support. Although they still need more maturation to be capable of independent respiration.
  • In the second trimester the baby’s size is increasing at an alarming speed, its movements and kicks become stronger too. They can now be felt by your partner too, when he keeps a hand on your tummy!

Some experts now believe that baby’s cry at birth is not his first cry. Silent cry in response to noise, stress and other things which cause displeasure to baby occurs inside uterus too and can be seen after 28weeks. The silent crying behavior in unborn baby are : opening the mouth with tongue movements;  short irregular breathings; settling back again!                                               



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