Childbirth and Pregnancy Week 38

Questions and Answers

What physiological change occurs in a mother about week 37 of her pregnancy?

Progesterone levels start to decrease. (correct)

The cervix widens substantially.

Oxytocin levels peak.

Estrogen levels significantly drop.

What is the effect of decreased progesterone levels in late pregnancy?

Increased sensitivity of the uterine muscles. (correct)

Inhibition of uterine contractions.

Decreased estrogen production.

Higher likelihood of premature labor.

What are Braxton Hicks contractions also referred to as?

False labor contractions. (correct)

Active labor contractions.

True labor contractions.

Prelabor contractions.

Which hormone increases in sensitivity due to the dropping levels of progesterone near term?

Oxytocin. Signup and view all the answers

Which structure is identified as the thin membrane surrounding the fetus?

Amniotic sac. Signup and view all the answers

About how many weeks is a full-term pregnancy typically?

38-1/2 weeks. Signup and view all the answers

What initiates regular contractions as the due date approaches?

Increasing oxytocin sensitivity. Signup and view all the answers

What is typically observed about the cervix during late pregnancy?

It becomes more constricted. Signup and view all the answers

What does the mucus plug do during pregnancy?

It seals the cervix to protect the fetus. Signup and view all the answers

At what dilation of the cervix does active labor begin?

4 centimeters Signup and view all the answers

What is the purpose of uterine contractions after the birth of the baby?

To detach the placenta. Signup and view all the answers

Which presentation has a higher risk during delivery?

Breech presentation Signup and view all the answers

What happens during the expulsion phase of labor?

The fetal head enters the birth canal. Signup and view all the answers

What is involution in the context of postpartum recovery?

The returning of the uterus to its pregestation size. Signup and view all the answers

What typically occurs when the amniotic sac ruptures?

Labor is likely to start soon. Signup and view all the answers

What is a Cesarean section (C-section)?

A surgical incision to deliver the baby. Signup and view all the answers

Why can a baby's skull compress during delivery?

The skull bones have not fused together yet. Signup and view all the answers

What role does relaxin play during pregnancy?

It loosens pelvic ligaments to facilitate childbirth. Signup and view all the answers

During the cervical dilation stage of labor, which hormone is primarily responsible for uterine contractions?

Oxytocin Signup and view all the answers

What is the typical diameter to which the cervix needs to dilate for vaginal birth?

10 centimeters Signup and view all the answers

How does the process of dilation during true labor primarily occur?

Through a positive feedback loop involving oxytocin and prostaglandins. Signup and view all the answers

Which statement about the pelvic outlet during childbirth is accurate?

It widens due to the action of relaxin. Signup and view all the answers

What process occurs as the fetus contacts the cervix during labor?

Stimulation of uterine contractions. Signup and view all the answers

What is the primary mechanism by which strong uterine contractions affect the cervix during labor?

They pull the cervix thinner and help it to open. Signup and view all the answers

What is one of the main reasons relaxin is important for childbirth?

It assists in the dilation of the cervix. Signup and view all the answers

What events occur during the cervical dilation stage?

Cervical effacement and dilation happen. Signup and view all the answers

What happens to the pelvic bones during pregnancy due to relaxin's effect?

The bones loosen slightly to accommodate the fetus. Signup and view all the answers

Study Notes

Pregnancy and Childbirth Overview

Full-term pregnancy typically lasts about 38-1/2 weeks, with childbirth often occurring within a week of the due date.
Physiological changes in the mother occur as pregnancy progresses, including a drop in progesterone levels around week 37, which allows for uterine contractions.

Hormonal Changes

Decreased progesterone levels increase the sensitivity of uterine muscles to oxytocin, stimulating contractions.
False labor contractions, also known as Braxton Hicks contractions, may occur due to lower progesterone without actual labor signaling.
The placenta secretes relaxin, which loosens pelvic ligaments and aids pelvic outlet widening for childbirth.

Stages of Labor

Three main stages of labor: cervical dilation, expulsion of the baby, and delivery of the placenta (afterbirth).
Labor can last from seven to 20 hours, depending on the progression of each stage.

Cervical Dilation Stage

Cervical dilation must reach approximately 10 centimeters for vaginal birth.
High levels of oxytocin trigger uterine contractions, which release prostaglandins, creating a positive feedback loop intensifying contractions.
The cervix thins out and opens during contractions, facilitated by relaxin.

Labor Signals

The mucus plug discharges from the cervix, indicating labor progression, and the amniotic sac may rupture, referred to as the "water breaking."

Active Labor and Expulsion Phase

Active labor begins when the cervix dilates to four centimeters, with increasingly strong and frequent contractions.
The expulsion phase starts when the baby's head enters the birth canal and ends with the birth of the baby.
The newborn's skull bones are flexible, allowing the head to fit through the birth canal.

Birth and Afterbirth

After the baby is born, the umbilical cord is cut, and post-delivery, the placenta is expelled from the uterus.
Uterine contractions help detach the placenta and assist in the shrinkage of the uterus, a process known as involution, returning organs to normal positions.

Presentation and Delivery Methods

Vertex presentation: the baby's head emerges first, allowing for a standard vaginal birth (most common).
Breech presentation: the baby's gluteal region or legs come out first, posing higher risks and often necessitating a Cesarean section (C-section) for safer delivery.
C-sections involve surgical incisions in the abdomen and uterus and are recommended when benefits surpass risks.

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Description

Explore the physiological changes in a mother's body as she approaches childbirth at week 38 of pregnancy. This quiz will test your understanding of key terms and concepts related to parturition, hormonal changes, and what happens as the due date nears.