Week 10 of pregnancy marks your baby's move into the fetal stage, which lasts until they're born (Moore et al 2019a). From now on, they’ll grow and develop, until they're ready for life outside your womb.
Your baby is about the size of a green olive. They measure about 3.1cm (1.2in) from head to bottom (crown to rump) and weigh nearly 4g (0.1oz) (Hill 2019a).
Your baby's head is more rounded and upright now, the outer part of their ears are fully developed and their limbs are well formed (Hill 2019b, Moore et al 2019b, Visembryo nd). Their eyelids are fused shut (Hill 2019b, Moore et al 2019b, Tawfik et al ), and will stay that way until about 27 weeks of pregnancy (Moore et al 2019a, Tawfik et al 2016).
Their tiny fingers and toes are no longer webbed (Hill 2019c, Moore et al 2019b, Visembryo nd), their arms and legs can rotate at their shoulder and hip joints (Hill 2019c, Mooney 2016a, b, Moore et al 2019c), and their hands meet over their heart (Mooney 2016a, Moore et al 2019c). Your baby may be small, but they're very active, kicking their new limbs (Moore et al 2019b, NHS 2018) and reaching up to touch their face (de Vries and Fong 2006).
The yolk sac, which provided your baby with nutrients before the placenta developed, will soon shrink (Tan et al 2012, 2014).
By week 10, your baby has a fully developed heart, which is beating at about 180 beats per minute. That's two or three times faster than yours (NHS 2018). Their other vital organs, including their kidneys, intestines, brain, and liver (now making red blood cells in place of the yolk sac), are starting to function, though they'll continue to develop throughout your pregnancy (Moore et al 2019a, b).
Discover how pregnancy can affect your body and your life at week 10 of pregnancy.
Inside pregnancy: 10-14 weeks
A 3D animated look at how your baby is developing in the first trimester of pregnancy. More inside pregnancy videos
Note: every baby develops differently. This page is designed to give you a general idea of how a fetus grows in the womb.
References
de Vries JIP, Fong BF. 2006. Normal fetal motility: an overview. Ultrasound Obstet Gynecol 27(6):701-11. obgyn.onlinelibrary.wiley.com [Accessed October 2019]Hill MA. 2019a. Fetal development. University of New South Wales Embryology. embryology.med.unsw.edu.au. [Accessed October 2019]
Hill MA. 2019b. Embryology: Carnegie stage 23. University of New South Wales Embryology. embryology.med.unsw.edu.au [Accessed October 2019]
Hill MA. 2019c. Embryology: week 8. University of New South Wales Embryology. embryology.med.unsw.edu.au [Accessed October 2019]
Mooney EK. 2016a. Hand embryology gross morphologic overview of upper limb development. emedicine.medscape.com [Accessed October 2019]
Mooney EK. 2016b. Lower limb embryology gross morphologic overview of lower limb development. emedicine.medscape.com [Accessed October 2019]
Moore KL, Persaud TVN, Torchia MG. 2019a. Fetal period: ninth week to birth. Chapter 6 in The developing human: clinically oriented embryology. 11th ed. Elsevier
Moore KL, Persaud TVN, Torchia MG. 2019b. Fourth to eighth weeks of human development. Chapter 5 in The developing human: clinically oriented embryology. 11th ed. Elsevier
Moore KL, Persaud TVN, Torchia MG. 2019c. Development of limbs. Chapter 16 in The developing human: clinically oriented embryology. 11th ed. Elsevier
NHS. 2018. You and your baby at 10 weeks pregnant. NHS, Health A-Z, pregnancy and baby. www.nhs.uk [Accessed October 2019]
Tan S, Pektas MK, Arslan H. 2012. Sonographic evaluation of the yolk sac. J Ultrasound Med 31(1):87-95. onlinelibrary.wiley.com [Accessed October 2019]
Tan S, Tangal NG, Kanat-Pektas M, et al. 2014. Abnormal sonographic appearance of the yolk sac: which can be associated with adverse perinatal outome? Med Ultrason 16(1):15-20. www.medultrason.ro [Accessed October 2019]
Tawfik HA, Abdulhafez MH, Fouad YA, et al. 2016. Embryologic and fetal development of the human eyelid. Opthal Plast Reconstr Surg 32(6):407-14. www.ncbi.nlm.nih.gov [Accessed October 2019]
Visembryo. nd. Carnegie stage 23: end of embryonic period. The Visible Embryo. www.visembryo.com. [Accessed October 2019]
