Late fetal development in the third trimester (weeks 28–40) is mainly about rapid growth, organ maturation, and preparation for life outside the womb.

The brain undergoes rapid growth in size and complexity

Development of gyri and sulci (folds) increases surface area

Improved neural connections

Sleep–wake cycles become more regular

Eyes open and close; can respond to light

Hearing is well developed → responds to sounds and voices

Increased coordinated movements:

Kicking, stretching, grasping

Pain perception

https://pmc.ncbi.nlm.nih.gov/articles/PMC10072285/#:~:text=Conversely%2C the American College of,1%2C 2%2C 11).

https://pubmed.ncbi.nlm.nih.gov/33048913/

Utilization of analgesia and anesthesia during fetal surgery began in the early 1980s,

US anesthesiology and fetal therapy consensus statement in 2021 recommends administration of fetal anesthesia in all invasive maternal-fetal procedures.

Lungs mature significantly

Increased production of surfactant (reduces alveolar collapse)

By ~34–36 weeks, lungs are usually capable of supporting breathing

Practice breathing movements occur (though no air is inhaled)

Heart is fully formed and functioning

Circulation is adapted to fetal life (e.g., ductus arteriosus still open)

Prepares for transition at birth when fetal shunts close

Rapid weight gain (most of it occurs now)

Fat deposition under the skin:

Helps with temperature regulation after birth

Skin becomes:

Less wrinkled

More opaque

Lanugo (fine hair) begins to disappear

Nails grow to fingertips

Hair on the scalp becomes thicker

Swallowing amniotic fluid regularly

Meconium (first stool) accumulates in intestines

Liver stores glycogen for energy after birth

Transfer of maternal antibodies (IgG) increases:

Provides passive immunity after birth

Fetus often settles into a head-down (cephalic) position near term

Size by Term (around 40 weeks)

Weight: ~3–4 kg

Length: ~48–52 cm

Current UK law

Continuation of the 24-week time limit and the 10-week limit on telemedicine,

agreed by Parliament in 2022 during the COVID-19 pandemic

New law

Remove the threat of police investigation, arrest, or prison for women ending their own pregnancy

New law applies regardless of gestational age

MPs back decriminalisation of abortion

https://www.bma.org.uk/news-and-opinion/mps-back-decriminalisation-of-abortion?utm_source=chatgpt.com

(Regardless of gestational age)?

BMA welcomes move it describes as ‘long overdue’ while maintaining issue is a healthcare matter (England Wales)

A vote in Parliament on 17 June (2025) saw lawmakers endorse the NC One (New Clause one) amendment to the Crime and Policing Bill,

which could see an end to the threat of criminal investigation and prosecution of women who choose to terminate their pregnancy.

MPs vote 379 to 137 in favour of the amendment

BMA medical ethics committee deputy chair

‘The passing of this amendment is a significant and long overdue step towards reforming antiquated abortion law in England and Wales….

‘Beyond this bill we will continue to push for wider reform of abortion law – including campaigning for the removal of criminal sanctions for medical professionals involved in abortions as part of their clinical practice….

The UK-wide decriminalisation of abortion has been BMA policy since 2017.

(46 minutes of backbench debate)

https://www.telegraph.co.uk/politics/2026/03/25/mps-urge-mahmood-block-decriminalising-late-abortions/

Lords move to decriminalise abortion up to birth

https://care.org.uk/news/2026/03/lords-move-to-decriminalise-abortion-up-to-birth

19th March 2026

Baroness Monckton tabled an amendment to the Bill in the Lords to remove the “radical proposal” which she said was passed in the Commons “without any evidence, scrutiny, public consultation or impact assessment”.

She argued that decriminalisation actually puts women in danger “by removing the current legal deterrent against administering an abortion away from a clinical setting right up to birth”.

Peers rejected the amendment, however, in a vote of 185 to 148.

MPs urge Mahmood to block decriminalising of late abortions

https://www.telegraph.co.uk/politics/2026/03/25/mps-urge-mahmood-block-decriminalising-late-abortions/

70 + MPs and Peers

Home and health Secretaries

“hit pause” on the plans

Signatories to the letter, 7 Labour MPs (404)

All eight Reform UK MPs

Baroness Hollins, the former head of the British Medical Association.

Kemi Badenoch, the Tory leader, have warned that the proposals lack “meaningful limits and safeguards”