SWARAJ HOSPITAL & RESEARCH INSTITUTE
BOLANGIR, ODISHA • OBSTETRICS & GYNAECOLOGY CLINICAL PATHWAY SERIES
Clinician Reference Infographic
Placenta and Fetal Nutrition
Fetal growth depends on the placenta, the mother's nutrition, and the fetus's own potential. This guide covers placental function, maternal nutrition, placental disorders, growth surveillance and Doppler, management of growth restriction and large babies, and care after birth, using the PLACENTA approach.
🎯 AT A GLANCE — PLACENTA AND FETAL NUTRITION
The placenta is the fetus's lung, gut, kidney, liver, and endocrine gland — it delivers oxygen and nutrients, removes waste, makes hormones, and filters some harmful substances
Fetal growth depends on three things: the mother's nutrition and health, placental function, and the fetus's own genetic potential
Small-for-gestational-age: estimated weight or abdominal circumference below the 10th centile; fetal growth restriction (FGR) is a small fetus that is failing to reach its potential (usually from placental insufficiency) — many small babies are healthy, and some normal-sized fetuses are restricted
Large-for-gestational-age (above the 90th centile) and macrosomia (birth weight 4000 g or more) mostly reflect maternal diabetes, obesity, and excess weight gain
Good nutrition before and during pregnancy, early detection of growth problems, and well-timed delivery reduce stillbirth, neonatal death, and lifelong disease
Check growth, not just size: serial measurements and Doppler separate constitutionally small babies from those at risk
🗺️ THE PATHWAY AT A GLANCE
1 · Before pregnancyNutrition, folic acid, weight, diabetes and anaemia control, stop smoking
2 · First trimesterDating scan, risk assessment, aspirin if high risk
3 · Mid-pregnancyAnomaly scan, placental site, uterine artery Doppler in at-risk women
4 · Third trimesterFundal height, growth scans, fetal movements, Doppler if small
5 · DiagnoseGrowth restriction or overgrowth, find the cause
6 · Deliver and feedTimed delivery, placental examination, early feeding, glucose checks
🫘 HOW THE PLACENTA WORKS
| Topic | Details |
|---|---|
| Development | Trophoblast invades the uterine wall and remodels the spiral arteries into wide, low-resistance vessels (complete by about 18–20 weeks); full maternal blood flow into the intervillous space from about 10–12 weeks; poor remodelling underlies pre-eclampsia and growth restriction |
| At term | Weight about 500 g (about one-sixth of the baby's weight), diameter 15–20 cm; cord about 50–60 cm with 2 arteries and 1 vein |
| Gas and water | Oxygen and carbon dioxide cross by simple diffusion; fetal haemoglobin binds oxygen more tightly than adult haemoglobin; flow depends on maternal perfusion and fetal circulation |
| Glucose | Crosses by facilitated diffusion (GLUT1 transporters); the main fetal fuel; fetal glucose follows maternal levels, so maternal hyperglycaemia drives fetal insulin and fat deposition |
| Amino acids and minerals | Active transport: fetal amino acid levels exceed maternal levels; iron, calcium, and vitamins are transferred actively; calcium transfer peaks in the third trimester |
| Fats | Free fatty acids and long-chain polyunsaturated fats (including DHA) cross selectively; most fetal fat is laid down in the third trimester |
| Antibodies | IgG crosses actively (mostly from about 28 weeks), giving passive immunity; preterm babies receive less |
| Hormones | Human chorionic gonadotrophin, progesterone, oestrogen, human placental lactogen (raises maternal insulin resistance so glucose reaches the fetus), placental growth hormone, corticotrophin-releasing hormone, placental growth factor |
| Barrier | Not complete: alcohol, nicotine, many drugs, and several infections cross (see the TORCH sheet); the placenta also inactivates some maternal cortisol |
🥗 MATERNAL NUTRITION IN PREGNANCY
| Topic | Details |
|---|---|
| Weight gain (Institute of Medicine) | Underweight (BMI under 18.5): 12.5–18 kg; normal (18.5–24.9): 11.5–16 kg; overweight (25–29.9): 7–11.5 kg; obese (30 or more): 5–9 kg; twins: larger ranges |
| Energy | No extra energy in the first trimester; about 350 kcal a day more in the second and third trimesters (ICMR–NIN and Institute of Medicine figures differ slightly) |
| Protein | Extra protein in the second half (about 10–25 g a day more): pulses, milk, eggs, fish, and meat |
| Folic acid | 400 µg daily before conception and in the first 12 weeks; 4–5 mg for a previous neural tube defect, epilepsy drugs, diabetes, or obesity |
| Iron and folic acid | WHO: 30–60 mg elemental iron daily; India: 100 mg elemental iron with 500 µg folic acid daily for at least 180 days from the second trimester; treat anaemia early |
| Calcium | WHO: 1.5–2 g daily in populations with low calcium intake to lower pre-eclampsia risk; India recommends about 1 g daily |
| Other micronutrients | Iodine (about 250 µg daily), vitamin D, vitamin B12 (vegetarians), zinc; avoid excess vitamin A |
| Balanced energy and protein supplements | WHO suggests them for undernourished women to reduce stillbirth and small babies; not for well-nourished women |
| Avoid | Alcohol, smoking and smokeless tobacco, caffeine above about 200 mg daily, unpasteurised dairy and undercooked meat or eggs (listeria, toxoplasma), high-mercury fish |
The first 1,000 days (conception to age 2) shape adult health: low birth weight is linked to later diabetes, hypertension, and heart disease — nutrition and growth are long-term investments
🔗 WHAT AFFECTS FETAL GROWTH
| Group | Examples |
|---|---|
| Maternal | Undernutrition, short stature, low pre-pregnancy weight, anaemia, hypertension, diabetes, renal or cardiac disease, antiphospholipid syndrome, smoking, alcohol, drug use, high altitude, young or older age |
| Placental and cord | Poor placentation, infarcts, abruption, placenta previa, accreta, abnormal cord insertion, single umbilical artery, twin-to-twin transfusion |
| Fetal | Chromosomal and genetic conditions, structural anomalies, and congenital infection (cytomegalovirus, toxoplasma, rubella, syphilis, malaria) |
| Large babies | Maternal diabetes, obesity, excess weight gain, previous macrosomia, post-dates, male sex, and genetic factors |
⚠️ PLACENTAL AND CORD PROBLEMS
| Disorder | Key points and action |
|---|---|
| Placental insufficiency and growth restriction | Small fetus with abnormal Doppler, often with oligohydramnios; see Step 4 |
| Pre-eclampsia | Shallow trophoblast invasion, raised soluble fms-like tyrosine kinase, and low placental growth factor; often with fetal growth restriction; aspirin prevention for high-risk women |
| Placenta previa | Placenta covering or near the internal os; painless bleeding; no vaginal examination; caesarean at 36–37 weeks if uncomplicated; a low placenta at the anomaly scan needs a repeat scan at about 32 weeks |
| Placenta accreta spectrum | Risk rises with previous caesareans and previa; plan delivery in a centre with blood, interventional radiology, and a surgical team |
| Placental abruption | Painful bleeding, tender hard uterus, fetal distress; resuscitate and deliver; watch for coagulopathy (see the haemorrhage sheet) |
| Vasa praevia and velamentous cord | Fetal vessels over the cervix; bleeding with membrane rupture and fetal bradycardia; elective caesarean at 34–36 weeks when diagnosed |
| Single umbilical artery | Look for other anomalies and monitor growth |
| Placental infection and infarcts | Malaria and other infections damage the placenta and cause low birth weight (see the malaria sheet) |
📏 SURVEILLANCE AND DOPPLER
| Tool | Details |
|---|---|
| Symphysis–fundal height | From 24 weeks, measure at each visit and plot on a growth chart; a lag of 3 cm or more, or a static or falling plot, needs a scan; fundal height alone misses many small babies |
| Ultrasound growth | Estimated fetal weight from head, abdomen, and femur measurements; abdominal circumference is the most sensitive; repeat no sooner than about 2 weeks; accurate dating matters |
| Umbilical artery Doppler | Pulsatility index above the 95th centile suggests placental resistance; absent or reversed end-diastolic flow signals severe disease |
| Middle cerebral artery Doppler | Low pulsatility index ('brain sparing') and a low cerebroplacental ratio indicate fetal redistribution, especially in late-onset growth restriction |
| Uterine artery Doppler | At 20–24 weeks, a high mean pulsatility index or notching identifies women at risk of pre-eclampsia and growth restriction |
| Ductus venosus | Absent or reversed a-wave is a late sign of cardiac compromise in early-onset growth restriction |
| Amniotic fluid | Deepest vertical pocket under 2 cm, or amniotic fluid index under 5, is oligohydramnios; often a sign of placental insufficiency |
| Cardiotocography and biophysical profile | Reduced variation on computerised cardiotocography, a low biophysical score, or decelerations indicate fetal compromise |
| Placental biomarkers | Placental growth factor and the soluble fms-like tyrosine kinase-1 to placental growth factor ratio help in suspected pre-eclampsia |
🛡️ FETAL GROWTH RESTRICTION
| Topic | Details |
|---|---|
| Definition | Consensus (Delphi 2016): estimated weight or abdominal circumference below the 3rd centile, or below the 10th with abnormal Doppler or a crossing of centiles; early-onset: under 32 weeks, late-onset: 32 weeks or more |
| Find the cause | Detailed anomaly scan; consider invasive testing or karyotype if early-onset or with anomalies (see the prenatal diagnosis sheet); test for infection (cytomegalovirus, toxoplasma, syphilis, malaria); look for maternal hypertension, renal, or autoimmune disease |
| What helps | Stop smoking; treat hypertension, anaemia, and infection; improve nutrition; low-dose aspirin (75–150 mg nightly from 12–16 weeks) lowers the risk in high-risk women; bed rest, extra supplements, and sildenafil are not proven |
| Monitoring | Growth every 2 weeks, Doppler weekly to twice weekly if abnormal, cardiotocography as indicated; daily fetal movement awareness |
| Timing of delivery (varies by guideline) | Reversed end-diastolic flow: about 30–32 weeks; absent end-diastolic flow: about 34 weeks; abnormal middle cerebral or uterine Doppler with growth restriction: about 36–37 weeks; small with normal Doppler: about 37–39 weeks; earlier for fetal compromise |
| Before preterm birth | Antenatal corticosteroids (under 34 weeks), magnesium sulfate under 32 weeks, delivery in a unit with newborn intensive care, continuous fetal monitoring in labour and a low threshold for caesarean |
📈 LARGE BABIES AND DIABETES
| Topic | Details |
|---|---|
| Screening for diabetes | India (DIPSI test): 75 g oral glucose, non-fasting, with a 2-hour plasma glucose of 140 mg/dL or more diagnostic (test at the first contact and again at 24–28 weeks); WHO and other criteria are also in use |
| Control | Diet and activity, glucose monitoring, insulin or metformin when targets are missed (fasting about 95 mg/dL or less and 2-hour after meals about 120 mg/dL or less); tight control lowers macrosomia |
| Suspected macrosomia | Ultrasound weight estimates are imprecise (error up to 15–20%); discuss the risks of shoulder dystocia, birth injury, and caesarean; caesarean is considered for estimated weight of 4500 g or more in diabetes and 5000 g or more without diabetes |
| Timing | Induction at 38–39 weeks may be offered for diabetes with a large baby; prepare for shoulder dystocia |
| The baby | Check blood glucose early and feed promptly; watch for hypoglycaemia, polycythaemia, jaundice, and respiratory distress |
🔬 EXAMINE THE PLACENTA AND FEED THE BABY
| Topic | Details |
|---|---|
| Examine every placenta | Complete? (cotyledons and membranes), weight, size, shape, infarcts, clots, calcification, cord insertion, length, and 3 vessels; placental weight to birth weight is about 1 to 6 at term |
| Send for histopathology | Stillbirth or neonatal death, fetal growth restriction, severe pre-eclampsia, abruption, preterm birth, severe anaemia in the baby, maternal sepsis, twin discordance, and abnormal placenta or cord |
| Small-for-gestational-age babies | Early skin-to-skin contact and breastfeeding; keep warm; check glucose in the first hours; watch for polycythaemia; fortify feeds if very small (see the premature newborn sheet) |
| Catch-up growth | Support exclusive breastfeeding for 6 months; avoid forced overfeeding; monitor weight, length, and head circumference |
| Mother | Counsel on diet, iron, interpregnancy interval of at least 2 years, and cardiometabolic follow-up after pre-eclampsia, diabetes, or a growth-restricted birth |
⚠️ COMMON PITFALLS
Relying on fundal height or palpation alone and missing growth restriction
Labelling every small baby as restricted, or reassuring a restricted baby because the weight is above the 10th centile
Reassuring about reduced movements without cardiotocography and ultrasound
Scanning too often (growth intervals under 2 weeks give unreliable results) or without accurate dating
Not looking for a cause (infection, anomaly, maternal disease) or not using aspirin in high-risk women
Overlooking diabetes and anaemia, or forgetting the newborn's glucose
Discarding the placenta without examining it
Memory Aid
PLACENTA
Eight steps for placental health and fetal nutrition.
P
Perfusion first — aspirin if high risk, treat hypertension, stop smoking
L
Look at growth — fundal height each visit; scans if at risk, 2 weeks apart
A
Assess with Doppler — umbilical, middle cerebral, uterine arteries
C
Counsel on nutrition — energy, protein, iron, folate, calcium, iodine
E
Evaluate the cause — infection, anomaly, maternal disease, diabetes
N
Notice reduced movements — assess the same day
T
Time the delivery — by Doppler, gestation, and fetal state
A
After birth — examine the placenta, feed early, check glucose
Remember: healthy placenta, well-fed mother, measured growth, timely delivery.
No comments:
Post a Comment