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Questions and Answers
Which of the following infections is associated with Sensorineural Hearing Loss (SNHL)?
Which of the following infections is associated with Sensorineural Hearing Loss (SNHL)?
The most severe teratogenic effects of Rubella occur before 16 weeks of gestation.
The most severe teratogenic effects of Rubella occur before 16 weeks of gestation.
True
What is the indication for Medical Termination of Pregnancy (MTP) in the context of Rubella?
What is the indication for Medical Termination of Pregnancy (MTP) in the context of Rubella?
Congenital rubella syndrome
The teratogenic period for Toxoplasma is primarily during _____ trimester.
The teratogenic period for Toxoplasma is primarily during _____ trimester.
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Match each teratogenic infection with its key manifestation:
Match each teratogenic infection with its key manifestation:
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What is a feature of congenital varicella syndrome?
What is a feature of congenital varicella syndrome?
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Neonatal varicella syndrome can occur if the pregnant female is infected 5 days before or 2 days after delivery.
Neonatal varicella syndrome can occur if the pregnant female is infected 5 days before or 2 days after delivery.
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What maternal infection can lead to fetal anemia?
What maternal infection can lead to fetal anemia?
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Zika virus is primarily transmitted through ______ bites.
Zika virus is primarily transmitted through ______ bites.
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Match the teratogenic conditions with their associated features:
Match the teratogenic conditions with their associated features:
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What is the total blood volume in the placenta?
What is the total blood volume in the placenta?
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The maternal blood in the placenta is contained entirely within the fetal blood vessels.
The maternal blood in the placenta is contained entirely within the fetal blood vessels.
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What type of villi is formed by cytotrophoblasts and appears around day 13 after fertilization?
What type of villi is formed by cytotrophoblasts and appears around day 13 after fertilization?
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The placental membrane is made up of several layers including the syncytiotrophoblast and the ________.
The placental membrane is made up of several layers including the syncytiotrophoblast and the ________.
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Match the following types of villi with their corresponding features:
Match the following types of villi with their corresponding features:
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What is the main function of the placenta?
What is the main function of the placenta?
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The oxygen saturation in the umbilical vein is typically between 80-90%.
The oxygen saturation in the umbilical vein is typically between 80-90%.
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What hormone does the blastocyst secrete to maintain the corpus luteum during pregnancy?
What hormone does the blastocyst secrete to maintain the corpus luteum during pregnancy?
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The corpus luteum degenerates after ______ weeks of pregnancy.
The corpus luteum degenerates after ______ weeks of pregnancy.
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Match each stage with its corresponding description:
Match each stage with its corresponding description:
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What is the typical weight of the human placenta at term?
What is the typical weight of the human placenta at term?
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The placenta is disc-shaped and directly contacts maternal blood.
The placenta is disc-shaped and directly contacts maternal blood.
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What condition is characterized by a placenta thickness greater than 4 cm?
What condition is characterized by a placenta thickness greater than 4 cm?
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A small placenta may be caused by uteroplacental insufficiency and is often associated with _____ growth restriction.
A small placenta may be caused by uteroplacental insufficiency and is often associated with _____ growth restriction.
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Match the following conditions with their associated features:
Match the following conditions with their associated features:
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What is the primary site of feto-placental circulation?
What is the primary site of feto-placental circulation?
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Nitabuch's layer plays a role in promoting deep implantation of the blastocyst.
Nitabuch's layer plays a role in promoting deep implantation of the blastocyst.
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What is the functional unit of the placenta called?
What is the functional unit of the placenta called?
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The rate of uteroplacental blood flow at term is approximately _____ ml/min.
The rate of uteroplacental blood flow at term is approximately _____ ml/min.
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Match the following terms with their correct descriptions:
Match the following terms with their correct descriptions:
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Which of the following drugs is known to cause fetal alcohol syndrome (FAS)?
Which of the following drugs is known to cause fetal alcohol syndrome (FAS)?
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ACE inhibitors are categorized as teratogenic drugs.
ACE inhibitors are categorized as teratogenic drugs.
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What severe cardiac condition is associated with lithium use during pregnancy?
What severe cardiac condition is associated with lithium use during pregnancy?
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Tetracyclines can cause discoloration of the __________ and __________.
Tetracyclines can cause discoloration of the __________ and __________.
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Match the following teratogenic drugs with their associated effects:
Match the following teratogenic drugs with their associated effects:
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What portion of the placenta does the fetal surface comprise?
What portion of the placenta does the fetal surface comprise?
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The maternal surface of the placenta appears shiny and grey in color.
The maternal surface of the placenta appears shiny and grey in color.
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What attaches to the fetal surface of the placenta?
What attaches to the fetal surface of the placenta?
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The maternal surface of the placenta is formed by the __________ basalis.
The maternal surface of the placenta is formed by the __________ basalis.
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Match the following surfaces of the placenta with their features:
Match the following surfaces of the placenta with their features:
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Which drug is associated with limb reduction defects and stillbirth?
Which drug is associated with limb reduction defects and stillbirth?
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Warfarin can lead to a condition known as Disala syndrome.
Warfarin can lead to a condition known as Disala syndrome.
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What teratogenic effect is linked to methotrexate?
What teratogenic effect is linked to methotrexate?
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Indomethacin can cause _____ closure of the ductus arteriosus when used past 32 weeks of gestation.
Indomethacin can cause _____ closure of the ductus arteriosus when used past 32 weeks of gestation.
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Match the following drugs to their associated teratogenic effects:
Match the following drugs to their associated teratogenic effects:
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What is the primary source of progesterone during the first 7 weeks of pregnancy?
What is the primary source of progesterone during the first 7 weeks of pregnancy?
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The placenta becomes the primary producer of progesterone after 10 weeks of pregnancy.
The placenta becomes the primary producer of progesterone after 10 weeks of pregnancy.
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What are the three estrogens primarily present in the mother during pregnancy?
What are the three estrogens primarily present in the mother during pregnancy?
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The __________ is the most common site of hormone production in the placenta.
The __________ is the most common site of hormone production in the placenta.
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Match the hormone with its type:
Match the hormone with its type:
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Study Notes
Varicella Zoster (Chickenpox)
- Pregnant females are at highest risk of transmission during the prodromal period.
- Congenital varicella syndrome can lead to severe complications like scarring, limb contractures, and may necessitate termination of pregnancy (MTP).
- Neonatal varicella syndrome occurs when a pregnant woman is infected within 5 days before or 2 days after delivery.
- Neonatal varicella syndrome can result in generalized rash, pneumonia, hepatitis, and meningoencephalitis.
Parvovirus B19
- In children, Parvovirus B19 infection presents with "slapped cheek" appearance and a lacy netline rash on the trunk.
- Pregnant women with a history of contact with school-going children should be aware of the risk of infection.
- Maternal infection can cause fetal anemia, polyhydramnios, and hydrops fetalis, potentially leading to heart failure.
Zika Virus
- Zika virus is a mosquito-borne teratogenic infection associated with significant fetal abnormalities.
- The virus has a unique affinity for TIM I, TAM, and AXL receptors.
- It specifically targets Heffbauer cells in the placenta.
- Infection can lead to severe neurological defects in the fetus, including:
- Cortical matter atrophy
- Microcephaly
- Increased limb tone
- Limb contractures
Other Conditions
- Hyperthermia: A fever of ≥ 1.5 °C during pregnancy can lead to neural tube defects, seizures, microcephaly, and intellectual disability.
- Phenylketonuria: Can result in microcephaly and cardiovascular system abnormalities in the fetus.
- Systemic Lupus Erythematosus (SLE): The presence of anti-Ro and anti-La antibodies can lead to congenital heart block in the fetus.
Teratogenic Infections
-
Cytomegalovirus (CMV):
- Most common vertical transmission occurs in the third trimester.
- The most severe infections can affect the developing fetus.
- Congenital CMV syndrome can lead to periventricular calcifications, microcephaly, chorioretinitis, and sensorineural hearing loss (SNHL).
-
Toxoplasma:
- Most common transmission period is the third trimester.
- The most severe infections can affect the developing fetus.
- Infection is often acquired through consumption of undercooked meat or contact with cat feces.
- Similar manifestations as CMV, but also includes hydrocephalus, intracerebral calcifications, and SNHL.
-
Rubella:
- Maximum transmission occurs during the third trimester (23-36 weeks).
- Most severe damage occurs up to 16 weeks of gestation.
- Requires screening during the first trimester.
- Susceptible women are IgM-negative and IgG-negative.
- Vaccination should be given after delivery.
Rubella:
-
Congenital Rubella Syndrome (Up to 16 weeks):
- Heart defects (patent ductus arteriosus, pulmonary stenosis)
- Eye abnormalities (cataracts, glaucoma)
- Ear damage (SNHL)
- Indication for MTP (Medical Termination of Pregnancy).
-
Post 36 weeks:
- IUGR (Intrauterine Growth Restriction)
Placenta Formation
- Decidua basalis: Essential for placental development, providing maternal support for the implanting blastocyst.
- Syncytiotrophoblast and Cytotrophoblast: These layers are critical for placental formation, forming the barrier between maternal and fetal blood.
- Total blood volume in Placenta: 500 ml, with 350 ml fetal blood within the villi and 150 ml maternal blood in the intervillous space.
-
Placental Membrane or Barrier: This barrier is composed of:
- Syncytiotrophoblast
- Cytotrophoblast
- Extraembryonic mesoderm
- Fetal capillary endothelium
-
Types of Villi:
- Primary Villi: Formed by cytotrophoblast at day 13 after fertilization.
- Secondary Villi: Develop at day 16, incorporating the trophoblastic shell and a mesodermal core.
- Tertiary Villi: Formed by day 17-21, further containing fetal blood vessels within the mesodermal core.
- Trophoblastic Invasion: This process is crucial for placental development, involving invasion of the maternal spiral arteries and modification of blood flow.
Placental Hormones and Functions
-
Main Functions:
- Respiratory exchange
- Hormone production
Respiratory Function
-
Oxygen saturation: The oxygen saturation in the intervillous space (IVS) mirrors the oxygen saturation in the umbilical vein, ranging from 65-75%.
-
Partial Pressure of O2: 30-35 mmHg in the IVS.
Corpus Luteum
-
Life Cycle:
- Day 1: Primary Follicle
- Day 14: Ovulation
- Secondary Corpus Luteum (CL): LH-dependent
- Day 22: Reaches maximum size and progesterone production.
-
Fertilization & Fate of Corpus Luteum:
- The blastocyst (specifically the syncytiotrophoblast) secretes hCG beginning on day 8 (day 22 overall).
- Corpus Luteum of Pregnancy: hCG-dependent, preventing degeneration.
- After approximately 10 weeks, hCG levels in the mother's blood decrease, leading to corpus luteum degeneration around 10 weeks.
Human Placenta
-
Characteristics:
- Shape: Discoidal
- Term Weight: 500 grams
- Placenta to Fetus Ratio (at term): 1:6
- Gestational Age (Placenta=Fetus Weight): 17 weeks
- Diameter: 15-20 cm (extending up to 22 cm)
- Thickness (Center): 2.5-4 cm
- Deciduate: Shedding after delivery
- Hemochorial: Direct contact with maternal blood
-
Placentomegaly: Placental thickness > 4 cm, often associated with conditions like:
- Multifetal gestation
- Diabetes
- Hydrops fetalis (Rh-negative pregnancy, Parvovirus infection, Thalassemia)
- Fetal anemia
- Infections (Syphilis, CMV)
- Chorangioma of the placenta
-
Small Placenta: Often associated with uteroplacental insufficiency and conditions like pre-eclampsia/eclampsia (PIH) and intrauterine growth restriction (IUGR).
Placental Circulation
-
Uteroplacental Circulation
- Site: Established within the intervillous space.
- Via: Spiral arteries
- Rate at term: 500-700 ml/min
- Uterine Blood Flow at term: 750 ml/min
-
Feto-placental Circulation
- Site: Within the villi
- Day of Establishment: Day 17 after fertilization
- Rate at term: 400 ml/min
- Fetal Blood Flow at term: 125 ml/min
Placental Cotyledon
- Description: The functional unit of the placenta, receiving blood supply via main stem villi and their branches.
Nitabuch's Layer
- Description: A layer of firbinoid degeneration situated between the blastocyst and decidua basalis.
- Function: Limits the penetration of the blastocyst into the maternal decidua.
- Clinical Relevance: Absence of this layer can lead to a deep blastocyst implantation, potentially resulting in morbidly adherent placentas or Placenta accreta spectrum (PAS).
Teratogenic Drugs
-
Category X Drugs: Absolutely contraindicated during pregnancy.
- Androgens/Testosterone
- DES (Synthetic estrogen)
- Warfarin
- ACE Inhibitors
- Tetracyclines: Can cause bone and teeth discoloration.
- Thalidomide
- Lithium
- Valproate: Leads to central nervous system defects, neural tube defects, congenital heart disease, and cleft lip/palate.
Teratogenic Drugs & Malformations
-
Alcohol: Fetal Alcohol Syndrome (FAS) (Mnemonic: Goa's famous beer bar)
- Growth restriction
- Abnormal facial features:
- Smooth philtrum
- Thin vermillion border
- Small epicanthal folds
- Abnormal brain development (microcephaly)
- Abnormal behavioral development (cognitive impairment)
-
Phenytoin: Fetal Hydantoin Syndrome:
- Midfacial hypoplasia
- Upturned nose
- Distal digital hypoplasia (may include cardiac defects)
- Oligohydramnios during the second and third trimesters
Other Important Drugs
- Isotretinoin: Microtia/anotia, CNS defects, cleft lip/palate
- Thalidomide: Phocomelia (proximal limb amputation), stillbirth
- Warfarin: Disala syndrome (chondrodysplasia, stippled epiphysis, nasal hypoplasia, CNS: corpus callosum agenesis, microcephaly, cataract)
- Methotrexate: Craniosynostosis (clover leaf skull)
- Tamoxifen (SERM): Similar to DES; vaginal adenosis, craniofacial defects, ambiguous genitalia. In mothers, it can cause endometrial cancer.
-
Misoprostol: Moebius syndrome (6th and 7th nerve palsy, limb reduction defects).
- Clinical Application: Contraindicated in first and second trimesters; can be used for cervical ripening in the third trimester.
- Indomethacin: After 32 weeks, premature closure of the ductus arteriosus.
Corpus Luteum
- Lifespan: 10-12 weeks
-
Hormones Produced:
- Progesterone (Pregnancy-maintaining hormone)
- Estrogen
- Inhibin A
- Relaxin
Placental Hormones
-
Hormones Produced:
- Steroids: Estrogen, progesterone ( earliest production by 8 weeks)
- Peptides: hCG, HPL, relaxin.
- Major site of hormone production: Syncytiotrophoblast
Important Notes on Placental Hormones:
-
Source of Progesterone in Pregnancy:
- Until 7 weeks: Corpus Luteum
- 8-10 weeks: Luteal-placental shift
- After 10 weeks: Placenta
- Ovarian Cyst in First Trimester: Distinguish if it's a corpus luteum, as its removal can impact hormone production.
- Dehydroepiandrosterone Sulphate (DHEA-S) is essential: DHEA-S converted to estrogen by placenta (specifically E3, followed by E2, after 9 weeks)
- Most common estrogens in the mother: E1, E2, and E3
Surfaces of Placenta
-
Fetal Surface: Comprises 4/5ths of the placenta.
- Chorion frondosum (cytotrophoblast layer)
- Shiny, grey appearance
- Umbilical cord attaches to the center
- Fetal membrane attached to the surface
-
Maternal Surface: Comprises 1/5th of the placenta.
- Formed by decidua basalis
- Dull, red color
- Divided into polygonal areas (lobes)
- Further subdivided into lobules/cotyledons (functional unit)
-
Note:* The diagram demonstrates the placement of the amniotic fluid and chorion between the fetal and maternal surfaces.
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Description
This quiz covers critical information regarding infections that can affect pregnancy, focusing on Varicella Zoster, Parvovirus B19, and Zika Virus. Learn about the risks, complications, and management associated with these infections in pregnant females and newborns.
