Which of the following statements about chorionic villus sampling is false?
Which of the following statements about abdominal pregnancy is true?
Number of stem villi at term in human placenta is?
What is the most common type of conjoint twin?
Which of the following conditions is ruled out in a twin pregnancy of the same age and sex?
IgM appears in fetus at what gestational age -
What is the expected rate of turnover of amniotic fluid in a pregnant woman?
Red degeneration of fibroid is seen in which of the following?
What is meant by 'Battledore insertion of placenta'?
The 'T' sign is associated with which condition?
Explanation: ***Is performed only in second trimester of pregnancy*** - This statement is false because **chorionic villus sampling (CVS)** is typically performed earlier in pregnancy, specifically during the **first trimester**, usually between 10 and 13 weeks of gestation. - Performing CVS only in the second trimester would negate one of its main advantages: providing earlier genetic diagnostic information than **amniocentesis**. *Is used for prenatal genetic diagnosis* - **CVS** is a primary method for **prenatal genetic diagnosis**, allowing for the detection of chromosomal abnormalities and genetic disorders. - It involves analyzing fetal cells obtained from the **chorionic villi**. *Villi are collected from chorion frondosum* - The sample for **CVS** is indeed collected from the **chorion frondosum**, which is the fetal part of the placenta containing numerous chorionic villi. - These villi are genetically identical to the fetus, making them suitable for **genetic analysis**. *Can cause limb deformities* - There is a recognized, albeit small, risk of **limb reduction defects** associated with CVS, particularly if performed very early in gestation (before 9-10 weeks). - This risk is part of the counseling provided to prospective parents considering the procedure.
Explanation: ***f6629bc8-61b2-4393-bb4c-9c32cd943e34*** - **Placenta acreta-like implantation** of the placenta into intra-abdominal organs or the abdominal wall makes removal dangerous due to potential damage and massive hemorrhage. - While leaving it in place can lead to serious complications like **infection**, **abscess formation**, or **secondary hemorrhage** as it degenerates, the risks of immediate removal often outweigh these, necessitating careful observation and management. *020c0067-d7b2-4fc2-85ae-2d6ba40ab437* - **Primary abdominal pregnancy** is extremely rare, accounting for less than 1% of all extrauterine pregnancies. - Abdominal pregnancies are generally **secondary** due to tubal abortion or rupture with subsequent reimplantation. *3560b92d-a63d-4966-8872-e4f56a82882f* - **Fetal survival rates** in abdominal pregnancies are very low, with a high incidence of **fetal anomalies** and **perinatal mortality**. - The abnormal placental implantation and lack of amniotic fluid protection lead to significant **growth restriction** and compression deformities. *5ab987e0-68ca-43f2-a8f2-238a5eb0c4f8* - The decision to remove the **placenta** in an abdominal pregnancy is complex and depends on its implantation site; often, it is left in situ due to the high risk of **hemorrhage** from attempting removal. - Removing the placenta can cause **uncontrollable bleeding**, especially if it is attached to vital organs or large blood vessels.
Explanation: ***240*** - At term, the **human placenta** contains numerous **stem villi** which branch extensively to form the villous tree. - The approximate number of **stem villi** at term is around **240**, contributing to the large surface area for maternal-fetal exchange. *60* - This number is significantly **lower** than the actual count of **stem villi** found in a mature, term placenta. - Such a low number would result in an **insufficient surface area** for effective nutrient and gas exchange. *120* - While higher than 60, this number is still **underestimated** for the quantity of **stem villi** present in a full-term human placenta. - A placenta with only 120 stem villi might not be able to adequately support a fetus at term. *480* - This number is an **overestimation** of the typical count of **stem villi** in a human placenta at term. - While villi are extensive, 480 stem villi represent a significantly higher number than usually observed.
Explanation: ***Thoracopagus*** - This type of conjoint twin, fused at the **thorax** and often sharing a heart and liver, is the **most common** variety, accounting for approximately **40%** of all cases. - The shared organs and complex anatomy often pose significant challenges for separation and survival. *Omphalopagus* - These twins are joined at the **abdomen** and typically share a liver, gastrointestinal tract, or other abdominal organs. - This is the second most common type, representing approximately **30-35%** of conjoint twins. *Craniopagus* - This rare form involves fusion at the **head**, often sharing parts of the skull, dura mater, or even brain tissue. - Due to the intricate neurological connections, craniopagus twins present exceptionally complex medical and ethical challenges, accounting for only **2-6%** of cases. *Rachipagus* - These twins are fused dorsally along the **spine** and typically share portions of the vertebral column and spinal cord. - This is an extremely rare type of conjoint twinning, representing less than **2%** of cases.
Explanation: ***Superfetation*** - **Superfetation** refers to the fertilization of an ovum when another pregnancy is already established in the uterus, resulting in two fetuses of **different gestational ages**. - As the question specifies a twin pregnancy of the **same age**, superfetation is ruled out. *Monozygotic twins* - **Monozygotic twins** originate from a single zygote that splits, resulting in genetically identical individuals of the **same sex** and age. - This condition is consistent with the given scenario of same-sex, same-aged twins. *Superfecundation* - **Superfecundation** is the fertilization of two or more ova from the same ovulatory cycle by sperm from **different acts of coitus** (which may involve different partners). - The twins are of the **same gestational age** (same cycle) but are **dizygotic**, and can be either the same sex or different sexes. - This condition is NOT ruled out by the criteria given in the question. *None of the following* - This option is incorrect because **superfetation** is definitively ruled out by the criteria of the question (twins of the same age).
Explanation: ***20 weeks*** - The fetal immune system begins to develop around **20 weeks of gestation**, at which point the fetus starts producing its own **IgM antibodies**. - **IgM** is the first antibody isotype produced by the developing fetal **B lymphocytes** and is important for early immune responses. *10 weeks* - While some components of the immune system may start to differentiate earlier, **IgM production** at a functional level is not yet established at **10 weeks of gestation**. - At this early stage, the fetal immune system is still primarily in its **developmental phase**, with major organogenesis occurring. *30 weeks* - By **30 weeks**, the fetus has already been producing IgM for several weeks, and the immune system is more mature, capable of a more robust **antibody response**. - While **IgG** levels are significantly increasing due to maternal transfer at this stage, **IgM production** began earlier. *at birth* - At birth, a neonate has circulating **IgM antibodies**, which are indicative of prior fetal immune activation and are measurable in umbilical cord blood. - However, the initial production of **fetal IgM** occurs much earlier in gestation, not at the time of birth.
Explanation: ***500 cc/h*** - The **amniotic fluid** undergoes a rapid and continuous turnover, with approximately **500 cc/h** being exchanged through multiple pathways. - This dynamic process ensures the constant renewal of the fluid, maintaining its critical functions for fetal development and protection. *1L/hr* - A turnover rate of 1 liter per hour is **higher than the physiological range** for normal amniotic fluid dynamics. - Such a high rate would imply an **abnormal fluid exchange**, potentially leading to imbalances. *1500 cc/h* - This rate represents an **extremely high turnover**, significantly exceeding the typical physiological exchange. - Sustained rates this high are **not consistent with normal amniotic fluid physiology** and could indicate underlying pathology. *2L/h* - A turnover rate of 2 liters per hour is **dangerously high** and far beyond the normal capacity for amniotic fluid exchange. - Such a rapid turnover would be **detrimental to fetal well-being** and is not observed in healthy pregnancies.
Explanation: ***Mid pregnancy*** - **Red degeneration**, or **carneous degeneration**, is most common during the **second and third trimesters of pregnancy** due to increased metabolic demands of the growing fibroid outstripping its blood supply. - The rapid growth leads to **ischemia**, hemorrhage, and necrosis within the fibroid, causing acute abdominal pain. *Early pregnancy* - While fibroids can grow in early pregnancy, **red degeneration** is less common as the uterine blood supply is generally still adequate to meet the fibroid's metabolic needs. - Other forms of degeneration, like **hyaline degeneration**, are more frequently observed in non-pregnant or early pregnant states. *Puerperium* - In the puerperium, fibroids typically undergo **regression** rather than degeneration, as the hormonal stimulation (estrogen and progesterone) that promoted their growth significantly decreases. - The uterus involutes rapidly, and fibroids often shrink. *Nulliparous women* - Nulliparous women can have fibroids and experience various forms of degeneration, but **red degeneration** specifically is rare outside of pregnancy. - Degeneration in nulliparous women is more commonly **hyaline** or **cystic** degeneration.
Explanation: ***Umbilical cord attached to the margin of the placenta*** - In a **Battledore insertion**, the **umbilical cord** inserts into the **edge** or **margin** of the placenta, rather than its center. - This unusual insertion resembles a **battledore**, a type of ancient racket or paddle with a handle at its edge (similar to those used in shuttlecock games). *Placenta attached to the margin of the membranes* - This description is more consistent with a **circumvallate placenta**, where the chorionic plate is smaller than the basal plate, leading to a rolled or folded margin of placental tissue covered by membranes, but it does not describe Battledore insertion. - In circumvallate placenta, the chorionic plate's edge rolls back and is surrounded by a ring of membranes, while Battledore refers specifically to the cord's insertion. *Placenta attached to the center of the uterus* - This simply indicates a **normal location** for the placenta within the uterine cavity and does not describe any abnormal insertion of the umbilical cord or specific characteristics of the placenta itself. - The placenta typically attaches to the uterine wall and can be central, fundal, or anterior/posterior, but this statement doesn't relate to the cord's insertion point. *Umbilical cord attached to the membranes* - This condition is known as **velamentous insertion of the umbilical cord**, where the cord blood vessels fan out within the amniotic membrane before reaching the placental tissue. - Velamentous insertion is a distinct anomaly from Battledore insertion and carries different risks, such as vasa previa and a higher risk of vessel compression or rupture.
Explanation: ***Monochorionic twin pregnancy*** - The **'T' sign** on ultrasound is highly suggestive of a **monochorionic twin pregnancy**, indicating shared placenta and a thin inter-twin membrane that meets the chorion at a sharp, T-shaped angle. - This sign identifies the absence of a chorionic plate extending into the inter-twin membrane, distinguishing it from thick-membraned dichorionic pregnancies. *Dichorionic twin pregnancy* - Dichorionic pregnancies typically exhibit the **'lambda' or 'twin peak' sign**, where the chorion extends into the inter-twin membrane, creating a triangular projection, not a 'T' shape. - This sign indicates two separate placentas (or fused but distinct placentas) and two chorions, leading to a thicker inter-twin membrane. *Normal singleton pregnancy* - A normal singleton pregnancy involves only one fetus, and therefore no inter-twin membrane or associated signs like the 'T' or 'lambda' sign are present. - The concept of chorionicity and amnionicity is specific to multiple gestations, particularly twin pregnancies. *Multiple gestation* - While a monochorionic twin pregnancy is a type of multiple gestation, the term "multiple gestation" is too broad and does not specifically identify the **'T' sign**. - Multiple gestation can be either monochorionic or dichorionic, and only monochorionic pregnancies are associated with the 'T' sign.
Fetal Assessment Techniques
Practice Questions
Hypertensive Disorders in Pregnancy
Practice Questions
Intrauterine Growth Restriction
Practice Questions
Multiple Gestation
Practice Questions
Rh Isoimmunization and Other Blood Group Incompatibilities
Practice Questions
Intrauterine Fetal Therapy
Practice Questions
Prenatal Diagnosis and Genetic Counseling
Practice Questions
Placental Abnormalities
Practice Questions
Preterm Labor and Delivery
Practice Questions
Management of Medical Disorders in Pregnancy
Practice Questions
Get full access to all questions, explanations, and performance tracking.
Start For Free