Aurora BayCare Medical Center (Green Bay, WI): The hospital where Meghan and the girls are now, and where the girls will be delivered.

Baby A: Lucy, self-designated

Baby B: Who the medical team is referring to as “Baby A”

Baby C: Who the medical team is referring to as “Baby B”

BPP: Biophysical Profile, a test that scores the babies via ultrasound on four fronts: (1) strong heart rates (2 points); (2) whether babies are practicing breathing (2 points); (3) whether little and big movements can be observed (2 points); and (4) ample amniotic fluid levels (2 points) = 8 total possible points. The babies receive daily BPPs; a score below 6 typically indicates need for immediate delivery. With the Dopplers, this is the test Dr. Hayes is monitoring most closely – it offers the clearest clues on whether babies are still best served in utero.

Diastolic flow: The waveforms that depict motion present in each baby’s umbilical artery indicating direction of blood flow to and from the baby and placenta. Ideal and normal diastolic flows moves in a forward direction. Intermittent flow (small gaps in the waveforms) is the earliest indication of fetal distress. Absent flow is an escalation, and its presence is what got Meghan admitted for inpatient care. Reverse flow is ominous and – unless very scant – sets off immediate delivery, as it means terminal complications are in effect (specifically heightened risk for this mess of syllables: intraventricular hemorrhage, bronchopulmonary dysplasia, and perinatal mortality).

Discordance: The degree to which the twins differ in size. Being identical, this should be 0%; anything above 25% is cause for alarm and points to TTTS and/or IUGR, both of which are precursors to (definitely) hyper-premature delivery and (maybe) fetal morbidity or death. Our girls’ discordance has swung from 26% to 17% to 48% to 19%, where we land now (13 Feb).

Doppler ultrasound: An imaging test to gauge diastolic blood flow, specifically from the placenta to baby. More here, and see also ‘Diastolic flow.’

Dr. Hayes: Our MFM doctor. By all accounts, a brilliant and (this part we love, in the nerdiest way) very erudite physician. He’s the doc to whom all difficult multiple pregnancies are referred, both locally and across the region.

Identical twins (or “Monozygotic twins”): Twins formed when one zygote splits into two. This type of twin occurs in .3% of all pregnancies, and there is no predilection by demographic. This type also isn’t subject to genetic predisposition, isn’t influenced by fertility treatments, and is considered universally “spontaneous.” In other words… what the heck just happened.

IUGR: Intrauterine Growth Restriction, the disorder in which one twin is indicating significantly lower growth than her co-twin. This is the condition impacting our Baby C. (Causation is hazy, but in brief: These girls are growing their miraculous, beautiful bodies by way of a broken placenta, of which Baby C has a much smaller share.)

Mono/di twins: Our girls! This abbreviation stands for “monochorionic diamniotic” = twins who share a placenta but have their own sacs. This is the second riskiest type of twins (and also indicates 100% that they’re identical). More here.

MFM: Maternal Fetal Medicine (the arm of obstetrics that handles high-risk pregnancies)

NICU: Newborn Intensive Care Unit

TTTS: Twin-to-Twin Transfusion Syndrome, the condition we believed could be afflicting the girls. More here.

Very preterm: The category of preterm babies we aspire to – though we’ll happily take “moderately preterm” or “late preterm,” too! Very preterm babies are born between 28 and 31+6 weeks. Their predicted health and morbidity is tied to significant challenges, including an extended stay in NICU and meaningful risk for blindness, deafness, and cerebral palsy. More here.

Week 30: The week at which our NICU doctor, Dr. Tsai, confirmed that risks for short- and long-term prematurity-related complications fall significantly. By this age, they may also be able to swallow, breathe fully on their own, and – be still our hearts – hold hands.