This lesson covers:
- The process of fertilisation and early embryo development
- What happens during gestation
Fertilisation and early embryo development
Several processes happen in the body before pregnancy can occur:
- Ovulation – This happens on day 14 of the menstrual cycle, when an egg cell is released by an ovary.
- Copulation – During sexual intercourse, the male ejaculates millions of sperm into the female’s vagina.
- Fertilisation – The egg cell and one sperm cell meet and fuse in the fallopian tube, forming a fertilised cell called a zygote.
- Cell division – After fertilisation the zygote starts dividing. When it reaches 32 cells, it is called an embryo.
- Implantation – The embryo reaches the uterus and implants into the uterine lining.
Gestation
After implantation the embryo continues to grow into a fetus. The development period inside the uterus is called gestation.
- At 1 Month – The embryo measures about 6 mm in length, with the brain, heart, eyes, ears, and limbs beginning to form.
- At 9 Weeks – Now around 25 mm long, all major body systems have started to form, and the term ‘fetus’ is used to describe the developing baby.
- At 3 Months – The fetus has grown to about 54 mm, and has facial features and body proportions.
- At 5 Months – Measuring around 160 mm, the fetus is active. Fine details like fingernails are also developing.
- At 7 Months – The fetus is about 370 mm long and has reached a stage of development where it could survive outside the womb under medical care.
- At 39 Weeks (Full Term) – The baby, approximately 520 mm long, is fully developed and ready for birth.
Practice Quiz
1. What is fertilisation?
Answer: Fertilisation is the process where a sperm cell from a male fuses with an egg cell from a female, resulting in the formation of a zygote, which is the first cell of a new individual.
2. When does ovulation occur?
Answer: Ovulation typically occurs around day 14 of a 28-day menstrual cycle, when an egg is released from the ovary.
3. What happens during copulation?
Answer: During copulation, or sexual intercourse, the male ejaculates millions of sperm into the female’s vagina, where they begin their journey to fertilise the egg.
4. Where does fertilisation take place?
Answer: Fertilisation usually occurs in the fallopian tube, which connects the ovary to the uterus.
5. What is a zygote?
Answer: A zygote is the single cell formed immediately after the fusion of a sperm and an egg, containing genetic material from both parents.
6. What happens to the zygote after fertilisation?
Answer: The zygote begins to divide through a process called mitosis, forming a cluster of cells that eventually develops into an embryo.
7. What is cell division in the context of early embryo development?
Answer: Cell division, specifically mitosis, is the process by which a zygote divides to form an embryo, increasing the number of cells and starting the formation of different tissues and organs.
8. What is implantation?
Answer: Implantation is the process by which the embryo attaches itself to the lining of the uterus, where it will continue to grow and develop.
9. What is gestation?
Answer: Gestation is the period of development from fertilisation to birth, during which the embryo and later fetus grows inside the mother’s uterus.
10. How long is the human gestation period?
Answer: The human gestation period typically lasts about 40 weeks, or approximately 9 months.
11. What are the key stages of embryo development in the first month?
Answer: In the first month, the embryo measures about 6 mm and begins forming the brain, heart, eyes, ears, and limbs.
12. When does the embryo become a fetus?
Answer: The embryo is termed a fetus at around 9 weeks of development when all major body systems have started to form.
13. What are the key developments at 3 months of gestation?
Answer: At 3 months, the fetus is about 54 mm long, has developed facial features, and body proportions begin to appear more human-like.
14. What significant changes occur at 5 months of gestation?
Answer: At 5 months, the fetus measures around 160 mm, is active, and fine details such as fingernails begin to form.
15. How developed is the fetus at 7 months?
Answer: At 7 months, the fetus is about 370 mm long, and has reached a stage where it could potentially survive outside the womb with medical care.
16. What is considered full-term for a pregnancy?
Answer: Full-term pregnancy is typically reached at 39 weeks, when the baby is fully developed and ready for birth.
17. What is the role of the placenta during gestation?
Answer: The placenta provides oxygen and nutrients to the developing fetus and removes waste products from the fetus’s blood.
18. How does the embryo get nutrients before the placenta is fully functional?
Answer: Before the placenta is fully functional, the embryo gets nutrients from the yolk sac and uterine secretions.
19. What are the functions of the amniotic sac and fluid?
Answer: The amniotic sac and fluid protect the fetus from physical shocks, provide a stable temperature, and allow the fetus to move freely, which is important for muscle and bone development.
20. What is the umbilical cord and its function?
Answer: The umbilical cord connects the fetus to the placenta, carrying oxygenated blood and nutrients from the placenta to the fetus and returning deoxygenated blood and waste products to the placenta.
21. What is morning sickness and when does it occur?
Answer: Morning sickness involves nausea and vomiting typically occurring in the first trimester of pregnancy, though it can happen at any time of day.
22. How does the uterus change during pregnancy?
Answer: During pregnancy, the uterus expands significantly to accommodate the growing fetus, increasing in size from about the size of a fist to the size of a watermelon.
23. What are Braxton Hicks contractions?
Answer: Braxton Hicks contractions are irregular, usually painless contractions that occur throughout pregnancy as the uterus prepares for labor.
24. How does the fetus develop its senses?
Answer: The fetus begins to develop its senses in the second trimester, with hearing developing around 18 weeks and other senses like touch and sight developing later in pregnancy.
25. What is the significance of fetal movements?
Answer: Fetal movements are a sign of a healthy pregnancy, indicating that the fetus is developing muscles and nerves properly.
26. How can expectant parents monitor fetal health?
Answer: Expectant parents can monitor fetal health through regular prenatal visits, ultrasounds, and tests like amniocentesis and non-invasive prenatal testing (NIPT).
27. What is the importance of prenatal vitamins?
Answer: Prenatal vitamins provide essential nutrients such as folic acid, iron, and calcium, which support fetal development and help prevent birth defects.
28. What is the purpose of an ultrasound during pregnancy?
Answer: Ultrasound is used to monitor the development of the fetus, check for any abnormalities, and determine the due date.
29. What are common pregnancy complications?
Answer: Common pregnancy complications include gestational diabetes, preeclampsia, preterm labor, and placental abruption.
30. How does the mother’s body prepare for labor?
Answer: The mother’s body prepares for labor through hormonal changes that soften the cervix, increase uterine contractions, and prepare the pelvic muscles for childbirth.
31. What are the stages of labor?
Answer: The stages of labor are the first stage (dilation of the cervix), the second stage (delivery of the baby), and the third stage (delivery of the placenta).
32. What is the role of oxytocin in childbirth?
Answer: Oxytocin is a hormone that stimulates uterine contractions during labor and helps with the delivery of the placenta and the initiation of breastfeeding.
33. What is an epidural and how does it work?
Answer: An epidural is a form of pain relief administered during labor through an injection in the lower back, which numbs the lower half of the body.
34. What is the difference between a natural and a cesarean birth?
Answer: A natural birth involves vaginal delivery of the baby, while a cesarean birth (C-section) involves delivering the baby through a surgical incision in the mother’s abdomen and uterus.
35. How is fetal distress monitored during labor?
Answer: Fetal distress is monitored through fetal heart rate monitoring, either externally with a belt around the mother’s abdomen or internally with an electrode attached to the baby’s scalp.
36. What is the Apgar score?
Answer: The Apgar score is a quick assessment of a newborn’s health, evaluating heart rate, breathing, muscle tone, reflex response, and color immediately after birth.
37. What are common signs of labor?
Answer: Common signs of labor include regular contractions, water breaking, back pain, and the baby dropping lower into the pelvis.
38. What is the role of a midwife or doula?
Answer: A midwife provides medical care and support during pregnancy, labor, and postpartum. A doula offers emotional, physical, and informational support to the mother during childbirth.
39. How does breastfeeding benefit the mother and baby?
Answer: Breastfeeding provides optimal nutrition and antibodies to the baby, promoting health and bonding. For the mother, it helps with uterine contraction and reduces the risk of certain cancers.
40. What is postpartum care?
Answer: Postpartum care involves medical check-ups, emotional support, and physical recovery for the mother, as well as care and feeding of the newborn.
41. What is colostrum and its significance?
Answer: Colostrum is the first milk produced by the mother after birth, rich in antibodies and nutrients, providing essential immune protection to the newborn.
42. What are the benefits of skin-to-skin contact after birth?
Answer: Skin-to-skin contact promotes bonding, regulates the baby’s temperature, heart rate, and breathing, and supports breastfeeding initiation.
43. What is neonatal jaundice and how is it treated?
Answer: Neonatal jaundice is a common condition where a newborn’s skin and eyes turn yellow due to high bilirubin levels. It is usually treated with phototherapy.
44. What are common newborn screenings?
Answer: Common newborn screenings include tests for genetic disorders, metabolic disorders, hearing tests, and congenital heart disease screenings.
45. How does prenatal care help ensure a healthy pregnancy?
Answer: Prenatal care helps monitor the health of the mother and fetus, detect and manage any complications, provide nutritional and lifestyle advice, and prepare for labor and delivery.
46. What lifestyle changes are recommended during pregnancy?
Answer: Recommended lifestyle changes include a balanced diet, regular exercise, avoiding harmful substances (tobacco, alcohol, drugs), and managing stress.
47. How do hormonal changes during pregnancy affect the mother?
Answer: Hormonal changes can cause various symptoms such as nausea, fatigue, mood swings, and physical changes like breast enlargement and skin changes.
48. What is gestational diabetes and how is it managed?
Answer: Gestational diabetes is a type of diabetes that develops during pregnancy. It is managed through diet, exercise, blood sugar monitoring, and sometimes insulin therapy.
49. What are the signs of preeclampsia?
Answer: Signs of preeclampsia include high blood pressure, protein in the urine, severe headaches, vision changes, and swelling in the hands and face. It requires medical attention.
50. How can partners support during pregnancy and childbirth?
Answer: Partners can support by attending prenatal appointments, helping with household tasks, providing emotional support, and being actively involved in the birth plan and labor process.