Institute of Health Sciences, State School of Higher Education, Biała Podlaska, Poland.
PKU Polyclinic, Institute of Mother and Child, Warsaw, Poland.
J Int Med Res. 2020 Sep;48(9):300060520934623. doi: 10.1177/0300060520934623.
Empirical determination of phenylalanine (Phe) tolerance in patients with phenylketonuria (PKU) relies on frequent assessment of blood Phe concentrations in relation to Phe intake from detailed meal records. This study aimed to determine Phe tolerance in twin pregnancies.
The reviewed cases included three women with PKU who each had a singleton and twin pregnancy (i.e., they were pregnant twice). All patients were under regular supervision to maintain Phe concentrations in a steady state and determine safe Phe intake. Restriction of Phe in the patient's diet was determined depending on the amount of Phe intake, which allowed for stable blood Phe concentrations within the target range.
In all three patients with PKU, the ratio of Phe tolerance during the course of the twin and singleton pregnancies was <1 for most of the pregnancy. The ratio of the increase in Phe tolerance between 29 and 34 weeks of gestation and that between 15 and 28 weeks of gestation was 0.66 and 1.17, 0.51 and 0.14, and 0.76 and 1.42 in the twin and singleton pairs of pregnancies, respectively.
Our study shows that Phe tolerance in a twin pregnancy is not greater than that in a singleton pregnancy.
通过详细的膳食记录，根据苯丙氨酸（phe）摄入量来评估血 phe 浓度，从而确定苯丙酮尿症（pku）患者的 phe 耐受能力。本研究旨在确定双胎妊娠时的 phe 耐受能力。
本研究回顾了 3 例 pku 患者，每位患者均经历了单胎妊娠和双胎妊娠（即两次妊娠）。所有患者均接受常规监测，以维持 phe 浓度处于稳定状态并确定安全的 phe 摄入量。根据 phe 摄入量来确定患者饮食中 phe 的限制，从而使血 phe 浓度在目标范围内保持稳定。
在所有 3 例 pku 患者中，在大多数妊娠期间，双胎妊娠与单胎妊娠过程中的 phe 耐受比值均<1。妊娠 29-34 周与 15-28 周之间 phe 耐受比值的增加在双胎和单胎妊娠中分别为 0.66 和 1.17、0.51 和 0.14、0.76 和 1.42。
本研究表明，双胎妊娠时的 phe 耐受能力并不大于单胎妊娠。
